## 1. Conceptual and Normative Argument on International Law



Recent philosophy of international law has pursued a great variety of
questions. For present purposes, they can be broadly grouped into two
categories, although the boundaries between them are not sharp. First,
there are conceptual questions, such as whether international law is
genuinely an instance of "law" and, if it is, how it is
related to the municipal legal orders associated with individual
states; there are also conceptual questions relating to key ideas
employed in international legal discourse, whether these be general
ideas such as "sovereignty", "the state", or
"legitimacy", or ideas associated with specific
international legal sources or doctrines, such as "customary
international law", "*jus cogens*", and
"human rights". Such questions are discussed mainly in
sections 2 and 3 of this entry.



Second, there are normative questions about the proper goals that
international law--or its domains, such as international human
rights law, international environmental law, and international
criminal law--should advance and the means by which it may
properly do so and, relatedly, how the legitimacy of international law
is to be assessed. A recurring issue is the extent to which
ethical-political standards fashioned to assess domestic
law--such as democracy, the rule of law, and even legitimacy
itself--apply to international law (an important theme in the
work of Buchanan, e.g., Buchanan 2013). Due to the long period of
philosophical neglect of international law, we are still at an early
stage in forming an adequate picture of the political morality
appropriate to its distinctive nature and role. These questions are
mostly discussed in sections 4, 5, and 6 of this entry.


## 2. International Law as Law



The two features of international law most commonly invoked by those
who call into question its legal character are the absence of a
centralized system of enforcement and the role of state consent in the
formation of rules of international law. Some legal philosophers,
while recognizing that international law possesses some features
characteristic of law, dispute its status as a genuine and
fully-fledged legal order (e.g., Hart 1961 [2012]). We consider these
different strands of arguments on the legal nature of international
law in turn.


### 2.1 Lack of Centralized Enforcement Mechanisms



At the domestic level, law is enforced through both executive power
(police, tax authorities, regulatory bodies, etc) and judicial power.
International law does not benefit from a comprehensive system of
executive and judicial enforcement that is comparable to what
developed domestic legal systems can offer. The UN, as the principal
international organization, does perform a unique role particularly in
the area of collective peace and security; and its most powerful
organ, the Security Council, is empowered to adopt decisions under
Chapter VII of the UN Charter that are binding on all member states of
the UN and can involve the use of military force. The Security Council
has used its enforcement powers since the end of the Cold War, most
notably during the First Gulf War in 1990-1991 when it
authorized its member States to use force to liberate Kuwait following
Iraq's aggression and invasion. But there are many examples of
grave breaches of international law that are not met with any
enforcement action by the Security Council. As for judicial
enforcement, international law lacks a centralized dispute settlement
mechanism that operates independently of the consent of states. It is
true, however, that the role of the International Court of Justice and
the proliferation of other international courts and
tribunals--with jurisdiction over areas such as human rights,
trade, investment, international crimes--mean that, in practice,
international law does benefit today from a far greater measure of
enforcement through courts and tribunals than ever in the past.



Some legal philosophers have responded to the problem of limited
enforcement by fashioning a theory of international law on the basis
of the hypothesis--admitted to be a
"fantasy"--that an international court with
compulsory jurisdiction exists and that there are reliable
international institutional mechanisms for giving effect to its
decisions (Dworkin 2013;
 section 4.4 below).
 Some have also given a normative interpretation of the relation
between law and enforceability that makes in principle, rather than
actual, enforceability a touchstone of legality. Thus, according to
Liam Murphy, when it comes to law



> 
> 
> we would regard it as obviously appropriate for provision to be made
> within the normative order itself for effective enforcement. Properly
> regulated third-party enforcement is always in principle appropriate.
> (Murphy 2017: 221).
> 
> 
> 



Another solution draws attention to the existence of decentralized
modes of enforcement, e.g., "outcasting", which operate
not through centralized institutions, but by denying law-breakers the
benefits of membership and cooperation (Hathaway & Shapiro 2011;
Kelsen 1952 [2012: 20-25]; Goodman & Jinks, 2013). Finally,
and more radically, some reject the thesis that enforcement
mechanisms, centralized or not, are necessary for full-fledged legal
status. It is a mainstream view in contemporary legal philosophy,
shared by philosophers as diverse as H.L.A. Hart, John Finnis, and
Joseph Raz, that the concept of law does not involve the idea of
coercion as a necessary element (Hart 1961 [2012: 199-200];
Finnis 2011; Raz 1999: 159; and in relation to international law,
O'Connell 2008: 62-8. For a different view, see Schauer
2015).



This mainstream view rejects the command theory of law (e.g., John
Austin), which construes law as orders of a sovereign backed by the
threat of sanctions; the view that the function of law is to identify
delicts (conduct characterized as illegal) which are the condition of
a sanction (a coercive act against the law-breaker) (e.g., Kelsen); as
well as predictive theories of law (e.g., Oliver Wendell Holmes) which
reduce law to predictions about the application of sanctions (Hart
1961 [2012]). Instead, the primary function of law is to provide a
structure for generating norms that guide human behaviour, with or
without the existence of effective sanctions, as in Joseph Raz's
hypothetical "society of angels" (Raz 1999: 159). On this
view, enforcement mechanisms operate as a mere contingent back-up plan
for cases where law fails in its primary function.



As a matter of historical fact, municipal legal systems have
extensively relied on centralized enforcement mechanisms to encourage
compliance, but this does not amount to a conceptual constraint on the
existence of law. It is also worth noting Hart's observation
that in the international domain--where it is difficult for
violence and wrong-doing to remain hidden from public view--there
may be less of a practical need for sanctions to secure compliance
(Hart 1961 [2012: 218]).



On this view, what matters for the existence of international law is a
sufficient level of compliance to underwrite its operation as a
practically effective system of normative ordering. Though some query
whether international legal norms genuinely exert compliance pull of
their own accord, as opposed to on the basis of independent (e.g.,
self-interested) reasons that favour adopting the pattern of behaviour
prescribed by law (Goldsmith & Posner 2005), in the famous words
of Louis Henkin, it is arguably still the case that



> 
> 
> almost all nations observe almost all principles of international law
> and almost all of their obligations almost all the time. (Henkin 1979:
> 47)
> 
> 
> 


### 2.2 The Role of Consent in the Formation of Rules of International Law



The most authoritative statement of the sources of international law
is found in Article 38 of the Statute of the International Court of
Justice (ICJ 1945). Neither of the two main sources of international
law there identified--customary international law and
treaties--has an obvious counterpart in domestic law. Arguments
about the legal character of international law turn, to a significant
degree, on how we understand these two methods of law creation to
function.



Legal philosophers writing about international law have often
proceeded on the basis that both treaty and custom ultimately depend
on state consent. Ronald Dworkin, for example, believed that the idea
that a state is subject to international law only insofar as it has
consented to be bound by it reflects what "seems to be now
generally accepted by practitioners and scholars of international
law" (Dworkin 2013: 5). The consent-based account of
international law does indeed enjoy wide support among international
lawyers too. In one 1996 case, the International Court of Justice
described consent, alongside sovereignty, as "*the very basis
of international law*" (ICJ 1996: para. 21).



But is the consent-based account correct in a descriptive sense? Does
it, in other words, accurately reflect the way in which rules of
international law are generated? When one considers how international
law "works", in theory as well as in practice, this
account begins to unravel. This was noted by H.L.A. Hart in 1961 when
he wrote of



> 
> 
> the suspicion that the general theory that all international
> obligation is self-imposed has been inspired by too much abstract
> dogma and too little respect for the facts. (Hart 1961 [2012:
> 226])
> 
> 
> 



State consent does evidently play an important role in the formation
of treaties. Treaties do not bind states that are not parties to them
and have not consented to be so bound (Vienna Convention on the Law of
Treaties, Article 34 [VCLT 1969]). But among treaties too, there are
important caveats. The right to withdraw unilaterally from a treaty,
which would grant states the full force of consent, does not, for
example, apply to all treaties. The UN Charter is generally understood
not to be open to unilateral withdrawal: member states of the UN can
be expelled from the organization, but they cannot leave it
voluntarily. Consent to it is thus irrevocable. States may be said to
have consented to all of the rules that descend from UN membership
when they first joined the UN, but the UN Charter is not a static body
of legal obligations; it also governs processes through which rules of
international law come into existence, and are interpreted and
developed--processes which will take their course after the
State's initial consent to be bound by the Charter.



The consent-based account runs into even greater difficulties when it
comes to custom. There is, first, the notion of *jus cogens*,
i.e., rules of customary international law (such as the prohibition on
torture, genocide and apartheid) which have acquired peremptory status
and from which no state is permitted to derogate. Dworkin maintained
that *jus cogens* too comes "under the umbrella of
consent" in contemporary international legal doctrine (Dworkin
2013: 6), but there is nothing in the definition of *jus
cogens* in the Vienna Convention that suggests
 this.[1]



Nor, contrary to many accounts, is customary international law, or
custom, based on consent. Custom is defined in the Statute of the
International Court of Justice as "general practice accepted as
law" (Statute of the International Court of Justice, Article
38(1)). This definition is normally understood to comprise two
elements: an objective one, i.e., the practice of States; and a
subjective one, i.e., *opinio juris*, the acceptance of rules
as custom. Many of the conceptual errors that afflict discussions of
custom, with inevitable repercussions for theoretical arguments about
international law, concern its subjective dimension. Two errors are
common. The first one is to think of *opinio juris* as
requiring state consent to a rule of customary international law.
Acceptance and consent are, however, different concepts. The
International Court of Justice regularly establishes the existence of
rules of customary international law without specific evidence of
consent from the states concerned (Talmon 2015). The second one is to
describe the subjective element as necessarily involving a belief that
a particular practice is already law.



There are at least two good descriptive reasons to be sceptical about
both the belief- and the consent-based theories of customary
international law. First, they cannot explain why newly independent
states are bound by rules of custom in respect of which they never had
an opportunity to give consent or time to form beliefs (Hart 1961
[2012: 226]). Secondly, neither the consent-based nor the belief-based
account of customary international law can adequately explain change
in customary rules. Under the consent-based theory, the replacement of
a rule of custom with a contrary one would be explained as a
consequence of states withdrawing their consent from, and acting in
breach of, the prior rule. Under the belief-based approach, a change
in custom would be explained by error or insincerity on the part of
states, either acting on the erroneous belief that a particular rule
was one of customary international law or lying about their
belief.



These descriptive questions have a bearing on conceptual argument
about the legal character of international law. If the main engines of
rule-creation function only on the basis of consent, or depend on the
belief and subjective mindset of those that those rules are meant to
constrain, the legal character of international law would be, at best,
severely diminished; or, at worst, lost entirely because international
law would be robbed of the claim to legitimate authority inherent to
law, a claim that its norms are binding simply as legal rather than as
voluntarily or otherwise subjectively assumed.



These questions also have an impact on argument about the legitimacy
international law, which is discussed below, because as observed by
John Tasioulas, such accounts "tarnish[*es*] the
legitimacy of customary international law" (Tasioulas 2014: 331;
Tasioulas 2016), and undermine both the moral and systemic credentials
of international law.


### 2.4 International Law as "Primitive Law": H.L.A. Hart's Critique



The most famous post-war critique of international law's legal
character is Chapter X of H.L.A. Hart's *The Concept of
Law*. Hart was not an outright sceptic about the legal character
of international law, saying we should "neither dismiss the
doubt we may feel... nor shall we simply confirm them"
(Hart 1961 [2012: 214]). However, he did think international law was
impaired in its law-like character by the fact that



> 
> 
> the rules for states resemble that simple form of social structure,
> consisting only of primary rules of obligation, which, when we find it
> among societies of individuals, we are accustomed to contrast to a
> developed legal system. (Hart 1961 [2012: 214])
> 
> 
> 



The resemblance is "in form though not at all in content"
(Hart 1961 [2012: 232]), given the discrepancy between the content of
obligations typically imposed by domestic legal systems and those
imposed by international law.



The main problem with international law, according to Hart, is that it
lacks secondary rules. This means it is not law in a modern developed
sense, but in a simple or primitive one. In Hart's well-known
conception, a legal system is a union of two sets of rules: primary
rules which impose obligations, and secondary rules which are rules
about rules, relating to the way in which those primary rules are
identified, changed and adjudicated
 upon.[2]
 Hart argues that international law possesses primary rules which are
for the most part observed in practice. International law however
lacks that distinctive secondary rule which Hart calls the the rule of
recognition, that is a rule that does not depend for its existence on
other rules and provides the ultimate foundation on which the legal
system depends.



These defects, Hart says, make international law not law in the modern
sense, but law only in a primitive or incomplete sense. Hart's
characterization of international law as primitive law is a poor fit
with his own view of primitive law as law suitable for



> 
> 
> a small community closely knit by ties of kinship, common sentiment,
> and belief, and placed in a stable environment. (Hart 1961 [2012:
> 92])
> 
> 
> 



The context in which international law operates is quite different:
the total number of States (fewer than 200) would fit the notion of
small community, but the small community of States has none of the
social ties that characterize the communities in which primitive law
operates.



A typical retort among international lawyers to Hart's critique
is that these are just matters of definition. But this answer misses
the distinction between terminological and conceptual disagreement.
Hart's conceptual critique of international law raises crucial
questions about its legal character. As Hart himself understood, a
failure to conceptualize the social phenomenon that we normally
describe as international law does matter, for it hinders both
"theoretical enquiries ... [and] moral deliberation"
(Hart 1961 [2012: 214]). We need to understand what it is that we are
talking about if we want to advance moral and political arguments
about international law.



More fundamentally, Hart's conclusion that international law
lacks a rule of recognition needs to be tested against the evolving
realities since 1961 when *The Concept of Law* was first
published. Hart was not particularly prescriptive about the form of
the rule of recognition:



> 
> 
> [i]t may, as in the early law of many societies, be no more than that
> an authoritative list or text of the rules is to be found in a written
> document or carved on some public monument. (Hart 1961 [2012: 94])
> 
> 
> 



But Hart was dismissive of the possibility that consent or *pacta
sunt servanda* could perform such a function: to say
"international law is what states have consented to" or
"international law obligations must be performed" cannot
amount to a rule of recognition.



A promising candidate for the role of secondary rule is the Vienna
Convention on the Law of Treaties, which is generally understood to
reflect customary international law. As a treaty about treaties, the
Convention has come to perform a systemic function by regulating the
adoption, entry into force, amendment and interpretation of treaties.
By providing rules for treaty-making, the Vienna Convention operates
for treaties much like the Uniform Commercial Code in the US or the
Code Civil in France do for contracts. It is, in other words, a set of
primary and secondary rules that enables certain promises to have
legal effect.



A basic norm to explain the legal character of the Vienna Convention
may be Article 38 of the Statute of the International Court of
Justice, a treaty to which all member states of the UN must also be a
party. But Article 38 is a treaty provision which, on first
inspection, does no more than identify the applicable law in disputes
brought before the Court. Applicable law clauses are far from
infrequent in treaties that provide for judicial settlement of
disputes, and their existence supports the non-systemic and episodic
nature of international law. So in what way can Article 38 be said to
be to embody the rule of recognition? Unlike other applicable law
clauses, Article 38 has come to perform a systemic function, and is
regularly relied upon by domestic as well as international courts. It
is foundational at least in an explanatory sense, i.e., as a rule
about how "primary rules may be conclusively ascertained,
introduced, eliminated, varied" (Hart 1961 [2012: 94]).



Lastly, in the search for a rule of recognition, some have pointed out
that features like the inability of states freely to leave the UN, to
take one example, have given a constitutional character to
international law. This is not only an exaggeration, but also a
distortion of international law--a conceptual over-correction of
not treating international law as properly law. Features such as the
non-denunciability of the UN Charter do however tell us something
important about the nature of international law: they may evidence a
distinctive constitutive force from which international law derives
full legal character.



The above responses to Hart's ambivalence about the legal status
of international law has granted his premise that a full-fledged legal
system requires a rule of recognition. Even on this basis, critics
like Jeremy Waldron have rejected his "very poor"
arguments for a qualified scepticism about the legal character of
international law (Waldron 2014: 213). However, Hart's leading
critic, Ronald Dworkin, contested this premise itself. According to
Dworkin, the determination of law is not ultimately grounded in a
social rule--a rule of recognition--widely accepted by
officials and others as the right standard for identifying
law. Instead, legal requirements emerge through a process of
"constructive interpretation" that requires the
interpreter to discern the set of underlying moral-political
principles that best *fit* and *justify* the relevant
legal materials, e.g., in the case of international law, the raw data
of treaties, state practice, *opinio juris*, international
declarations, etc. (Dworkin 1986). Unlike Hart, Dworkin's view
of international law is part of his theoretical ambitions to establish
that genuine law is morally binding on its subjects (see
 section 4
 on Legitimacy).


## 3. States and Sovereignty



The criteria for determining the existence of statehood are
well-established in customary international law (Crawford 1979 [2006:
38]). They are: a defined territory, a permanent population, an
effective government, the capacity to enter into relations with other
States, and independence. Each of these criteria is related to an
equally fundamental aspect of international law and inter-state
relations: sovereignty. The relationship between sovereignty and
statehood is crucial in both legal philosophy and international legal
practice. Although some consider sovereignty to be coextensive with
independence, James Crawford's seminal work on statehood
maintains that whereas independence is a prerequisite for statehood,
sovereignty "has another more satisfactory meaning as an
incident or consequence of statehood" (Crawford 1979 [2006:
89]). This section will explore the various aspects of this
"more satisfactory meaning."



Sovereignty can be viewed as the ultimate authority that derives from,
and attaches to, statehood. On the international plane, though
international organizations exercise some functions normally
associated with States, it is traditionally only States that have been
described as sovereign. This may now be changing as some argue that
the European Union, for example, possesses a kind of sovereignty, with
its member States now being sovereign in a different,
"late" or post-national, sense (MacCormick 1993 [2006: 4,
16]; Walker 2003, 9). On the domestic plane, the position is more
complicated given that a larger number of subjects--from monarchs
to parliaments, from individuals to peoples--have, at various
points and in different ways, been considered sovereign (Verdirame
2016).


### 3.1 Absolute Sovereignty



Identifying the matters over which sovereign states have, or should
have, ultimate authority is a difficult task in both an explanatory
and normative sense. An enduring view is that the sovereignty of the
State is absolute; a sovereign state is the final arbiter in all
domestic matters, with limitations to such absolute sovereignty
permissible only where the state has consented to them. Under this
view, the subject matter of state sovereignty covers all legal and
political matters that relate to a state's territory and people.
Hobbes is the early modern thinker most commonly associated with this
all-encompassing conception of sovereignty. This interpretation of the
few brief passages on international relations in the
*Leviathan* is questioned by some scholars (Malcolm 2002), but
it remains the foundation for theories of absolute sovereignty in
international political thought.



The problem with theories about absolute sovereignty is that they can
only, at best, support a narrow consent-based idea of international
law which, as the discussion of the sources of international law in
the earlier section has shown, does not reflect the reality of how
rules of international law are created, interpreted and applied. Some
classical international law thinkers writing in the natural law
tradition, like Alberico Gentili (Wagner 2017), argued that it was
possible to reconcile absolute sovereignty with a fuller idea of
international law by postulating that only voluntary (i.e., positive),
but not involuntary (i.e., natural law), rules imposed by
international law on states impinge on the concept of absolute
sovereignty. In other words, one can be absolutely sovereign and still
subject to natural law.



With the exception of this particular natural law tradition,
proponents of the absolute conception of sovereignty have generally
been viewed as "*deniers of the* "Law of
Nations"" (Hinsley 1986: 184). The criticism is that there
can be no international law unless it is accepted that, on
*some* matters at least, states must be irrevocably subject to
an authority other than their own; the possibility of subjection to an
external authority must be viewed as a necessary requirement for even
minimal international law.



The absolute conception of sovereignty also cannot be reconciled with
the UN Charter, which recognizes the principle of "*sovereign
equality*" in Article 2--the same provision where other
cornerstones for the post-war order, such as the peaceful settlement
of disputes and the prohibition on the use of force, are laid. As a
matter of positive international law in force today, states are not
fully sovereign--i.e., they are not the final arbiters--on
matters pertaining to the use of force. In particular, they are not
free to develop a set of rules governing the use of force that
contravenes the prohibition in the UN Charter, nor do they have any
legal means of escaping such rules by withdrawing their consent. The
same can be said of other fundamental principles and rules, such as
self-determination and human rights.



Yet international law still describes states as sovereign. The
principle of sovereignty equality constructs a world order where
states are endowed with ultimate authority over some matters, yet
inescapably subject to the authority of international law in others.
(For a defence of the idea of sovereignty as a vital mechanism for
ensuring the authority of international law in an ineradicably
pluralistic world in which states disagree on what constitutes a just
and legitimate internal public order, see Roth 2011).



That said, it is important not to confuse sovereignty in this sense of
ultimate authority with the idea of economic or political power. For
example, to say that the States that emerged from the collapse of the
European empires after World War II acquired sovereignty on an equal
basis as their former colonies is to say that they were endowed with
the ultimate authority to decide matters--such as the regulation
of social and economic activities in their territory--which had
hitherto been the domain of the colonial powers. Whether these newly
independent States also acquired the socio-economic or political clout
to take on, for example, big multinational corporations operating in
their territory, or whether they became more powerful politically than
the former colonial powers, is another matter. To use a different
example, by leaving the European Union, the United Kingdom regained
sovereignty over matters which (unlike colonies of course) it had
freely agreed to transfer to the European Union during the time of its
membership, but whether this increase in sovereignty means an increase
in power or influence is a different matter. Authority can be bestowed
upon those that have no power, and power can be wielded by those with
no authority.


### 3.2 Self-Determination



There is another fundamental concept that must be factored in to
explain the role of sovereignty in modern international law:
self-determination. Self-determination is prominently mentioned in
Article 1(2) of the UN Charter as one of the purposes of the UN. Under
international law, self-determination is a right of all peoples,
defined in identical terms in the Charter and the UN International
Covenants on Civil and Political Rights (1966) and Economic, Social,
and Cultural Rights (1966), as the right to "freely determine
their political status and freely pursue their economic, social and
cultural development."



Self-determination is considered to have both an external and internal
dimension (Crawford 1979; Alston 2017). The external dimension, namely
the right of a people to be free from colonial subjugation or foreign
occupation and control, was historically most transformative at the
time of decolonization (Crawford 1979). The internal dimension
concerns the rights of people to pursue democratic governance
domestically (Franck 1992) and has become increasingly relevant in
discussions about the role of international law in promoting
democracy.



Self-determination complicates the meaning of sovereignty in
international law. It is conceptually cognate to moral and political
ideas of popular sovereignty and self-government, which are, in turn,
related to the values of self-respect and autonomy. By embracing this
notion, international law gave recognition to the moral and political
value of self-government, accepting that people prefer to be ruled by
their own bad rulers rather than foreigners, including those
foreigners with some claim to greater competence.



Self-determination adds a new dimension to argument about sovereignty
in international law also because it is no longer only states that
advance a claim to ultimate authority--in some sense, and to some
degree, people can too. This means that international law is no longer
immune from tensions between the state and the people that have
featured prominently in many political struggles. In cases of
secession (Crawford 1979; Buchanan 2008) in particular, the claim of
the extant state to ultimate authority can be challenged by a
population now empowered to articulate a competing claim under the
banner of an internationally recognized legal principle (the legal
merits of such competing claims will, of course, vary).



If sovereignty is thought of as a quality that both states and peoples
possess, the analogy between sovereignty and human autonomy, advanced
by Timothy Endicott, makes more sense. Moreover, understood as both
complete power within a political community and complete independence
needed for the purposes of a good state, sovereignty is compatible
with the legitimate authority of international law and ameliorates the
worry about abuses (Endicott 2010). Such power and freedom must be
subject to law but, just as with individual autonomy, it is wrong to
think that these qualities must be forgone as a price for such
subjection.


### 3.4 International Organizations and Sovereignty



The phenomenon of international organization adds further conceptual,
moral and political challenges to the idea of sovereignty. The key
question is one that Rousseau first posed in the *Emile*:



> 
> 
> How far should the rights of an international federation be stretched
> without destroying the rights of national sovereignty? (1762 [1979:
> 466])
> 
> 
> 



The context is different in the sense that, instead of the single
international federation envisaged by Rousseau, international law has
developed through a multitude of universal and regional international
organizations.



But questions about the boundaries between the domestic and the
international legal sphere, and their respective institutions, are
even more important nowadays as international organizations exercise
functions that once were within the exclusive domain of states. These
questions lie at the heart of the most recent debates about
international law, populism (Muller 2016; Alston 2017) and the
rise of authoritarian international law (Ginsburg 2020). Some question
the dualism or pluralism on which these arguments are premised, and
prefer to think of domestic and international law as forming part of
the same legal order. Kelsen was the most famous proponent of these
"monist" conceptions (Bernstorff 2010; for another attempt
to show the compatibility of state sovereignty with the authority of
international law with the notion of changing sovereignty regimes and
constitutional pluralism, see Jean Cohen 2010).



An important set of normative questions concerns the relationship
between international organizations and political and individual
liberty. Some argue that while the transfer of sovereign functions to
international organizations can be justified for a number of moral and
political reasons, it cannot extend to the point where it jeopardizes
human rights or hollows out self-government--these limits are
necessary to preserve the liberal character of the international order
(Verdirame 2013).



Many contemporary writers focus on the European Union, which has been
described as "supranational", rather than international,
in light of the direct primacy that EU law enjoys within domestic
legal spheres (Neyer & Wiener 2011a; van Middelaar 2013). Whether
supranationalism is a way of ascribing sovereignty to the European
Union or a way of reconceiving the legal order in a
post-*sovereignist* and cosmopolitan sense is an open debate
(Eriksen 2011). For others, the process of European integration poses
a challenge to the modern liberal constitutional sense of sovereignty
as understood to include the "overall competency and
responsibility for the common welfare of the people united into a
polity....", and the shift of the regulatory power over the
economy away from the State risks paving the way for "a
fragmentation of the care for the common good"
(Bockenforde 1997).



These normative concerns become more acute in the case of a fully
fledged world government. Kant, in *Perpetual Peace*, reached a
famously sobering conclusion on the prospect of international
organizations developing into such a world government:



> 
> 
> The idea of the right of nations presupposes the separation of many
> neighbouring states independent of one another; and though such a
> condition is of itself a condition of war (unless a federative union
> of them prevents the outbreak of hostilities), this is nevertheless
> better, in accordance with the idea of reason, than the fusion of them
> by one power overgrowing the rest and passing into a universal
> monarchy, since as the range of government expands laws progressively
> lose their vigour, and a soulless despotism, after it has destroyed
> the seed of good, finally deteriorates into anarchy. (Kant 1795 [1996:
> 336])
> 
> 
> 



One of the leading contemporary political and legal philosophers,
Joseph Raz, shares Kant's scepticism about world government, but
argues that there may be a better alternative to world government than
a world of sovereign states. That alternative is one of relatively
sovereign states, which are however subject to binding regulations
issued by international organizations (Raz 2019).



The balancing act between cosmopolitan international law (i.e., law
that binds all states) and domestic sovereignty is famously explored
in John Rawls' *Law of Peoples* (Rawls 1999; see also
Wenar 2008 [2021]). Rawls himself does not use the concept
"sovereignty", or "state", in relation to the
societies that are members of his "Society of Peoples",
but that is because he associates "sovereignty" with an
absolutist conception, and regards "states" as claiming
such sovereignty. In contrast, his theory upholds a more restricted
notion of sovereignty for "well-ordered peoples". Such
peoples enjoy both legitimacy with respect to their own citizens and
full international standing in the Society of Peoples, which includes
immunity from intervention.


## 4. Legitimacy


### 4.1 Senses of Legitimacy



There are multiple ways of assessing the various dimensions of
international law, such as its individual norms or bodies of norms
(e.g., international human rights law, humanitarian law etc.) and its
associated institutions and enforcement mechanisms (e.g., the
International Court of Justice, Security Council resolutions, etc).
Some of these assessments relate to how international law and
institutions bear on a given state's interests or policy
preferences; others are in terms of efficiency or impact on economic
growth; some are more overtly moral forms of assessment, invoking
demands of peace, the rule of law, justice, environmental protection,
and so on. Of course, a key debate in international relations concerns
the extent to which moral values find a foothold in an international
domain that is "anarchic" in the sense of lacking a
sovereign political authority or reliable enforcement mechanisms.



One prominent moral-political rubric for assessing international law
is the contested idea of "legitimacy". Sometimes
"legitimacy" is used as a catch-all term encompassing any
kind of assessment of law, but this usage is too broad. A
starting-point in achieving greater specificity is the distinction
between *de facto* (or descriptive) and *de jure* (or
normative) interpretations of legitimacy. Sometimes talk of the
"legitimacy" of international law is a matter of
describing the degree to which it is accepted, or complied with, by
its putative subjects, primarily states. On this *de facto*
interpretation, an international legal norm will enjoy legitimacy to
the extent that it exerts a high level of "compliance
pull" among international actors. A substantive study of de
facto legitimacy investigates the features that tend to enhance
support for, and compliance with, international law (Franck 1995).



By contrast, *de jure* senses of "legitimacy" refer
to the capacity of international law to generate reasons for action of
various kinds. These might be reasons, whether prudential or moral, to
establish international laws and institutions, to preserve and develop
them once they exist, or not to interfere with their operations
(Buchanan 2013). But *de jure* legitimacy is often taken to
mean something more ambitious: the existence of a "right to
rule". On this view, some domain or institution of international
law enjoys *de jure* legitimacy to the extent that its putative
subjects have a *pro tanto* or defeasible moral obligation to
comply with its directives, one that is content-independent, i.e., not
dependent for its binding force on the specific content of any
particular law (Raz 2006; Green 2004 [2012]). This sense of *de
jure* legitimacy, as the right to rule, corresponds to the kind
legitimate authority that states are often interpreted as asserting in
relation to their members.



Just as it is controversial whether international law is truly law,
some have also raised doubts as to whether international law should be
assessed in terms of the "right to rule" asserted by
states. A lot of international law takes the form of treaties that
bind only states that are parties to them. It might seem that the idea
of a promise or contract, rather than that of legitimate rule, is the
right template for assessing the normative force of such treaties.
Moreover, the other main source of international law, customary
international law, being the product of the convergent practice and
attitudes of disparate state actors, does not assert a right to rule
in the way that a unitary ruler, whether an individual or group, such
as a legislative body, does. Yet others have claimed that, insofar as
we can impute a claim to rule to international law, it is not as
strong as that made by states, but amounts instead to a claim of the
existence of a moral reason for maintaining and conforming to
international law, not in a content-independent moral obligation
(Buchanan 2013).



But assuming that a right to rule is an assertion plausibly imputable
to international law and institutions, how can we determine whether it
is ever justified? The question is rendered all the more acute by the
fact that in recent decades international law has increasingly
asserted a more expansive right to rule, one that encroaches into
areas previously regarded as belonging to the domain of state
authority, including such matters as the basic rights of its own
citizens, economic and environmental policy, and the provision of
vital goods such as education and health care.


### 4.2 Consent Theory



One prominent approach traces the legitimacy of international law to
the actual consent (explicit or implicit) of its subjects. States are
bound by treaties insofar as they consent to them; meanwhile, states
are bound by customary international law insofar as they have
explicitly (*opinio juris*) consented to its norms in the
process of their formation, or else implicitly done so (e.g., by
failing persistently to object to them). One problem with the consent
theory is that international law includes norms that purport to bind
states independently of whether they consented to them, such as norms
that came into being before the state came into existence, or norms
that have achieved the status of *jus cogens* norms (Dworkin
2013). In response, the steadfast defender of the consent view might
reply, "So much the worse for the legitimacy of these
norms".



Even if we were to accept this hard-line response, a deeper challenge
remains: why, if international law can help us achieve vital
goals--such as the avoidance of war, prevention of human rights
abuses or the mitigation of climate change--on condition that all
states generally comply with it, should its authority over them be
subject to their consent? The question is all the more pointed once it
is recognized that the governments of many states do not themselves
enjoy the consent of their own subjects or even perpetrate grave
injustices against them. Considerations such as these have led many to
conclude that, contrary to received views, actual consent is not in
general a necessary condition for international law's legitimacy
but is, at best, an idea that plays an important but limited role in
explaining the bindingness of treaties. Nor, it has been argued, is
actual consent generally a sufficient condition for legitimacy, since
state consent to treaties that require the commission of human rights
abuses would not be even presumptively binding (Buchanan 2010;
Tasioulas 2010; Murphy 2017).



One familiar move is to resort to a hypothetical version of consent
theory, appealing not to the actual consent of states, but to
international standards that states have good reason to accept. Such a
view is propounded by Rawls in *The Law of Peoples,* which
envisions legitimate international law as grounded in principles
("the Law of Peoples") that would be endorsed in social
contracts at two levels: first, among liberal peoples as regulating
foreign relations among themselves; second, among liberal peoples
together with a sub-category of non-liberal peoples--decent
hierarchical peoples. Rawls' account, however, is problematic in
a number of ways. First, it presupposes that decent hierarchical
principles enjoy legitimacy with respect to their own populations
despite not adhering to basic liberal rights, such as freedom of
speech and non-discrimination on the grounds of sex or religion.
Second, and relatedly, the doctrine of human rights embodied in the
Law of Peoples is very minimalist, excluding not only the
aforementioned rights, but also socio-economic rights such as the
rights to health, work, and an adequate standard of living. Finally,
despite its minimalism, Rawls' Law of Peoples is ultimately
grounded in the perspective of liberal societies--the only
members of the Society of Peoples that are "fully
reasonable". But given that "reasonableness" is
defined by stipulation as stemming from ideas implicit in liberal
democratic culture, rather than by reference to an objectively true
criterion, the whole approach is vulnerable to accusations of
parochialism. (For another attempt to mobilize Rawlsian approach to
international legal legitimacy, with a focus on the great pluralism
that characterizes the international order, see Roth 2011:
ch.2-4).


### 4.3 The Service Conception



Difficulties with consent-based, or voluntarist, theories have led to
the exploration of alternative bases for the legitimacy of
international law, especially in relation to those obligations not
traceable to a treaty. The two following approaches are not only
non-voluntarist, but they also make reference to objective standards
of reason. One approach is inspired by Joseph Raz's influential
"service conception of authority", which advances a Normal
Justification Condition (NJC) on legitimate authority. According to
the NJC:



> 
> 
> A has legitimate authority over B if the latter would better conform
> with reasons that apply to him if he intends to be guided by A's
> directives than if he does not. (Raz 2006: 1014; Tasioulas 2010, 2013)
> 
> 
> 



The NJC purports to specify a generally applicable sufficient
condition of legitimate authority. An important feature of it is that
it does not present the legitimacy of international law in an
all-or-nothing manner, and this is so in two ways (Tasioulas
2010). First, it may be that some areas of international law (e.g.,
the law on the use of force) enjoy legitimacy, whereas others (e.g.,
international trade law) do not. Second, it may be that some states
are bound by a given area of international law, such as human rights
law, whereas others are not. This is because the former, but not the
latter, would better comply with reasons that apply to them by being
bound by that international legal regime, whereas others would
not. This second possibility enables the Razian theory to accommodate
the possibility of a justified exceptionalism in relation to the
legitimate authority of international law. This is one potential
template for defending familiar claims that the United States, for
example, is not bound by norms on the use of force that properly bind
other states because it should be free to use its immense capabilities
to further the cause of justice around the globe in ways that other
states cannot. But a similar argument for exceptionalism might be
pressed in the case of weaker or poorer states in relation to
international obligations--for example, pertaining to free trade
or environmental protection--that are unduly burdensome for
them.



Leaving aside the possibility of exceptionalism, the Razian theory
faces the challenge of how to integrate a proper respect for state
sovereignty. To what extent, for example, does a due regard for
sovereignty entail that there are certain matters that fall within the
jurisdiction of states and regarding which international law cannot
invalidate or override their decisions? The question is broadly
analogous to that which arises in the domestic context: to what extent
is the authority of the state limited by a due respect for the
autonomy of its citizens, such that the state should not seek to
impose obligations with respect to certain matters, e.g., selection of
occupation or spouse, even if its directives would lead to greater
compliance by citizens with reasons applicable to them? Of course, the
state is an institution, one lacking the basic moral status of
individual human beings, but the question arises because of the value
of collective identity and self-determination that is protected by
sovereignty. In this connection, Raz has controversially proposed a
mutually exclusive relationship between state sovereignty and a sound
international human rights law (Raz 2010). Over and above state
sovereignty as a constraint on the legitimacy of international law,
there is a more general question of how such authority is constrained
by a proper principle of subsidiarity that favours the resolution of
political questions at the most local level possible (Follesdal
1998; Finnis 2016). Finally, a special challenge arises regarding
international law's claim to legitimate authority in the absence
of its creation through democratic means, especially in relation to
states that are themselves democracies (see section 4.5).



Questions arise, however, about the extent to which any domain of
international law can achieve legitimacy in these terms, especially
given the absence of reliable enforcement mechanisms at the global
level. This is because, on the NJC, one way in which legitimacy can be
acquired is through the capacity of legal institutions effectively to
impose solutions to various societal problems--such as
co-ordination problems regarding environmental
protection--through its capacity to enforce the standards it lays
down. This reveals the familiar substantive dependence of *de
jure* legitimacy on *de facto* legitimacy: the fact that
the subjects of law are likely to comply with it enhances its
legitimacy. Some have questioned whether international law can claim
any legitimacy given the absence of reliable enforcement mechanisms
(Posner 2009). This is a problem that is especially acute in the area
of international human rights law, since the usual expedient of a
tit-for-tat response to another state's defection from the law
seems out of place here. It will hardly be an incentive for state X to
comply with international human rights law if state Y threatens
non-compliance in relation to its own citizens.



But even in the case of international human rights law, various
responses have been offered. One line of response calls into question
the need for the "enforcement" of international law to be
global in character. The seminal work of Beth Simmons on the
effectiveness of human rights treaties has shown that, insofar as
membership of such treaty regimes tends to enhance human rights
compliance, the mechanisms through which this is achieved are
primarily those of domestic politics rather than a "white
knight" foreign state or international agents (Simmons 2009).
More generally, as we saw above (SS2.1), states in general tend to
conform with their international legal obligations (Henkin 1979: 47).
Another line of response appeals not to the effectiveness of
international law, but its supposed epistemic superiority, deriving
from its pooling of cross-cultural knowledge in identifying solutions
to common problems, such as the content of human rights (Buchanan
2008). However, it is doubtful that a bare claim to epistemic
superiority can justify a claim to practical, as opposed to
theoretical, authority, i.e., a claim about what we have reason to do,
as opposed to what we have reason to believe (Tasioulas 2013).


### 4.4 The Principle of Salience



An alternative way of dealing with the legitimacy of international
law, given the absence of reliable enforcement mechanisms, is offered
by Ronald Dworkin (2013). For Dworkin, legitimacy concerns not only a
moral obligation of obedience, but one that is reliably
*enforceable* through the courts. Given the absence of any
international court with compulsory jurisdiction and reliable
enforcement mechanisms, it could be argued that on this interpretation
of legitimacy the question of international law's legitimacy
simply does not arise. As we noted previously (2.1), Dworkin avoids
this sceptical conclusion by proceeding on the "fantasy"
that such a court exists, that cases can be readily brought before it,
and that there are effective sanctions to enforce its rulings. Dworkin
claims we can discern the binding requirements of international law by
asking:



> 
> 
> What tests or arguments should that hypothetical court adopt to
> determine the rights and obligations of states (and other
> international actors and organizations) that it would be
> *appropriate* for it to enforce coercively? (Dworkin 2013:
> 14)
> 
> 
> 



Two more general obligations are then appealed to by Dworkin in
answering this question.



The first is a general obligation incumbent upon all states to
undertake steps that enhance their own political legitimacy, as well
as of the international legal order in which states operate. Such
steps include


1. upholding human rights at home and abroad;
2. guaranteeing the assistance of the international community against
invasion and other external threats to a state's
independence;
3. encouraging international cooperation; and
4. enabling people to have some role in their own government (Dworkin
2013: 18).



But this obligation of mitigation suffers from considerable
indeterminacy, given the existence of reasonable disagreement about
the best way to improve the legitimacy of the existing international
legal order. As a remedy, Dworkin invokes a second basic obligation on
states, the principle of salience:



> 
> 
> If a significant number of states, encompassing a significant
> population, has developed an agreed code of practice, either by treaty
> or by other form of coordination, then other states have at least a
> prima facie duty to subscribe to that practice as well, with the
> important proviso that this duty holds only if a more general practice
> to that effect, expanded in that way, would improve the legitimacy of
> the subscribing state and the international order as a whole. (Dworkin
> 2013: 19)
> 
> 
> 



The result is that a state will be "prima facie" bound to
comply with an emerging consensus, of the kind described, if doing so
will enhance its legitimacy, and it will enhance its legitimacy if
compliance would help ameliorate some of the four problems of the
state system identified above. Applying this principle, Dworkin
believes that the basic elements of the UN system, including the UN
Charter, the Geneva Conventions, the conventions on genocide, and the
Rome Statute of the International Criminal Court, have acquired
salience of this kind, such that all states now have an obligation to
obey them as law, irrespective of whether they have consented to them
(Dworkin 2013: 20).



Dworkin's resort to fantasy, however, raises questions. Critics
of a Razian persuasion will claim that an appeal to a fantasy court is
necessitated only by Dworkin's adoption of an unduly restrictive
conception of legitimacy centred on the judicial enforcement of law.
But the essence of legitimate authority is the existence of a
content-independent obligation of obedience, not the subsidiary
question of whether it is properly enforceable, let alone enforceable
through the courts. Another difficulty is that it seems problematic to
derive obligations to obey international law here and now on the basis
of a fantasy scenario that bears little relation to any existing, or
reasonably foreseeable, reality. For example, why should the fact that
there is plausibly an obligation to obey the International Criminal
Court in a hypothetical world in which it operates impartially and
effectively tell us anything much about states' obligations in
the current world in which its impartiality and effectiveness are
matters of heated controversy? At a more methodological level, many
will baulk at Dworkin's tendency to run together the question of
the existence of international law with that of its legitimacy, since
they would reject his thesis that law is of its nature presumptively
legitimate (Tasioulas 2021). For some other treatments of the
legitimacy of international law, see Besson, Christiano, and Pettit in
Besson and Tasioulas (2010); also regarding particular institutions,
such as courts Follesdal 1998)).


### 4.5 Democracy



Some believe there is an intimate link between democracy and political
legitimacy, at least in the domestic context. They regard the
democratic enactment of law, or at least the subjection of any source
of law to democratic control, as a necessary condition of its
legitimacy, if not also a sufficient one. But even many of those who
do not treat democracy as a universally necessary or sufficient
condition for legitimacy--such as advocates of the service
conception or the salience principle--accept that democratic
law-making processes augment the legitimacy of the laws they produce.
Of course, the proper characterization of democracy is itself a
contested matter--ranging from simple majoritarianism, on the one
hand, to sophisticated deliberative conceptions of democracy, on the
other. For present purposes, however, we can take democracy to involve
the idea of participatory self-government, in which those subject to
laws participate as free and equals in deliberation and
decision-making leading to the enactment of laws.



Various difficult questions arise as to the relationship between
international law and democracy, such as whether non-democratic states
should have full sovereign status or whether international law should
encourage the spread of democracy around the globe, perhaps by
recognizing and upholding a human right to democracy (Franck 1992 and
1995: ch.4; Dworkin 2013). However, two other questions are
particularly salient under the rubric of legitimacy: (1) should the
process of international law-making be democratic?, and (2) can
international legal norms enjoy legitimacy in the case of democratic
states that have not consented to be bound by them?



Regarding the first question, it is obvious that existing systems for
the generation of international law (e.g., custom and treaties) are
not meaningfully "democratic". International law is
created by states, many of which are not themselves democratic, and
the process by which they create such law cannot itself be described
as democratic. However, many writers have advocated introducing
democratic features into international law-making. One example is
Ronald Dworkin, who canvassed the idea of establishing a world
legislative body through a Global Legislative Convention. The body
would operate by means of a four-majorities system. Proposed laws
would need to receive votes representing states with a majority of the
UN General Assembly's members' total populations, a
majority of votes in the General Assembly, a majority of votes in the
Security Council, and a majority of votes among the Council's
permanent members (Dworkin 2013: 28). One potential concern about this
proposal is that it operates via majorities among *states*
(weighted to some extent by their populations), rather than among all
individual persons throughout the globe. This worry may be mitigated
somewhat if we suppose that the states participating in this process
must themselves be sufficiently representative of their
populations.



Others, however, defend more ambitious schemes that involve the direct
representation of the global population. For example, Thomas Franck
proposed towards the transformation of the UN General Assembly into a
bicameral forum, with one chamber for states and another being
directly elected (Franck 1995: Part V; for other such proposals of
global democratic institutions, including a global direct
"virtual" democratic assembly, see Held 1995; Falk &
Strauss 2000). Democratic reforms of this sort attract scepticism not
only on the basis that states are unlikely to cede power to a global
democratic populace, but also because genuine democracy requires forms
of entitlement, deliberation and solidarity (e.g., equal rights of
participation, a robust civil society (e.g., mass political parties to
mediate between individuals and officials, concern for a common good,
etc) that cannot be realistically replicated at the global level). In
this sceptical vein, Thomas Christiano has written that global
democracy



> 
> 
> is highly unlikely to succeed given the weakness of global civil
> society and it is highly unlikely to be legitimate given the
> unevenness of stakes and given the high chance of permanent
> minorities. (Christiano 2010: 137)
> 
> 
> 



He prefers, instead, the idea of a fair association of democratic
states operating on the basis of a constrained principle of consent.
(For a discussion of international legitimacy from a neo-republican
perspective that incorporates democratic elements, see Pettit
2010).



The second question, identified above, is whether democratic states,
in particular, have an obligation to obey international legal norms
they have not consented to or incorporated into their domestic law
through democratic procedures. Recent international law, especially
through expansive conceptions of customary international law and
*jus cogens*, has significantly increased the number of norms
which bind states, even in the absence of their consent. This has
created a backlash, especially among "neo-conservative"
commentators who deny that any such laws can bind a constitutional
democracy, at least in the absence of its consent expressed by means
of internal democratic processes (Rabkin 2005; Kyl, Feith, & Fonte
2013). But this sort of concern extends beyond neo-conservative
defenders of American exceptionalism; for example, Martha Nussbaum, a
leading liberal political philosopher, has argued that domestic
democratic endorsement is a condition of international law's
legitimacy (Nussbaum 2018
 [Other Internet Resources]).



Given that existing international law-making processes are not even
weakly democratic, and that there is no realistic prospect that they
will become so anytime in the foreseeable future, why should they be
regarded as binding on democratic states in the absence of their
consent or democratic incorporation into their own legal systems? The
problem of integrating international and democratic governance is one
of the most serious challenges facing us today, and it is echoed in
similar challenges confronting regional governmental blocs, such as
the European Union, that assert authority over their constituent
democratic member states.



One line of response begins by arguing that democracy is not the
ultimate touchstone of legitimacy, whether of international or
domestic law, and that, for example, consent theory, the service
conception of legitimate authority, or the principle of salience can
justify the international legal order's legitimacy even in
relation to democratic states. This line of thought leaves unaddressed
specific worries regarding how intrusive international law can be with
respect to the decision-making of democratic states without
compromising or forfeiting its claim to legitimacy or causing undue
damage to domestic democratic governance. For a sophisticated attempt
to articulate ways of arriving at an acceptable balance between the
goods of international law and constitutional democracy, see Buchanan
and Powell 2008. A notable element of their account is the defence of
"principle M", i.e.,



> 
> 
> where the acceptance of international law by a constitutional
> democracy can be reasonably expected to result in *constitutional
> changes*--significant alterations in constitutional
> structures or significant diminutions in political
> self-determination--then, as with other constitutional changes
> (such as consensual secession, accession to a federation, or
> devolution from a centralized state), there is a strong presumption
> that public constitutional deliberation and popular choice are
> required. (Buchanan & Powell 2008: 347)
> 
> 
> 


## 5. International Rule of Law


### 5.1 The Rule of Law--Thick and Thin



One of the key determinants of the legitimacy of a legal order is the
extent of its compliance with the widely acclaimed, but deeply
contested, value commonly designated as "the rule of law".
An initial problem is that the phrase "the rule of law" is
used to mean many different things. It is important to avoid confusing
the rule *of* law with the idea of rule *by* law. The
latter refers to the idea of governance through the means, and under
the constraint of, positive law. But the fact that a mode of
governance assumes a recognizably legal form does not necessarily
reveal anything about its value. When the expression "rule of
law" is used to mean rule by law, there is no meaningful
difference between, for example, a call to respect the rule of law in
international relations and a simple call to respect international
law.



If, however, we think of the rule *of* law as an evaluative
notion, different and important issues arise. One of them is whether
the rule of law properly extends to the evaluation of international
law and, if so, under which interpretation and with what concrete
implications. This debate partly reflects background disagreements
about the rule of law more generally. Another downstream question is
to what extent, and in what form, the ethical-political ideal of the
rule of law, has been, or should be, specified as a set of legal
requirements within international law itself, analogously to the
manner in which international human rights law crystallizes a
background morality of human rights (Arajavi 2021). In this section,
the focus will be on the prior, more foundational issue.



Legal philosophers disagree about the proper characterization of the
rule of law, their differing views occupying varying points along a
spectrum from "thin", or formal-procedural, to
increasingly "thick", or substantive, accounts (Waldron
2016; Tasioulas 2020a). "Thick" accounts of the rule of
law identify it with something approaching all the requirements,
formal-procedural and substantive, good law should satisfy; or all the
requirements that make for legitimate law (Beyleveld & Brownsword
2007); or all the demands of political justice (rights) that bear on
law (Dworkin 2011); or else some favoured comprehensive catalogue of
legally-relevant desiderata, such as compliance with democracy and
human rights (Bingham 2010; Annan 2004). The thicker one's
favoured account of the rule of law, the more demanding a standard it
sets for the international legal order. This has led some advocates of
thick accounts to conclude that the rule of law does not apply to
international law, since it imposes demands that cannot feasibly be
made of international, rather than domestic, law.



One such advocate of a thick account is James Crawford, a former Judge
on the International Court of Justice. Crawford identifies five
requirements imposed by the rule of law:



> 
> 
> first, that no one is outside the law, still less above it; second,
> that it is by some means or in some sense democratic, at least in the
> sense of being accountable to others; third, that its instituted
> authorities--notably the Security Council--are in principle
> subject to legal constraint; fourth, that there is something like a
> constitution of international society; and fifth, that society is not
> irremediably unjust. (Crawford 2014: 343)
> 
> 
> 



As Crawford shows, existing international law in general struggles to
meet each of these desiderata; at best, perhaps only certain
"enclaves" of international law do so (Crawford 2014:
367).



One might conclude from his analysis that full compliance with the
rule of law is an unrealistic demand to place on the international
legal order, ignoring, as it does, salient disanalogies between the
domestic and international spheres, such as the absence of a
centralized legislative authority, courts with compulsory
jurisdiction, and effective enforcement mechanisms, as well as forms
of international solidarity needed to make democratic governance
feasible. Crawford himself draws the conclusion that there can only be
a rule of law in international law in the thin, formal, sense
(Crawford 2014: 375), not the full, substantive, sense incorporating
all five of his requirements. (For more optimistic proponents of
"thick" conceptions of the international rule of law, one
that incorporates respect for human rights, see McCorquodale 2016 and
Pavel 2021).



Others, who are proponents of the thin view of the rule of law, will
respond to Crawford's conclusion by saying that the
"thin" view of the rule of law is the correct one in
general. For these philosophers, "thick" accounts of the
rule of law err in lumping together a series of requirements on law
that either have no underlying coherence or which simply replicate
other standards for its evaluation, thereby obscuring the distinctive
form of assessment imported by a thinner account of the rule of law as
one moral-political demand upon law among others (Tasioulas
2020a).


### 5.2 Thin Theories of the International Rule of Law



International law may fare better on "thin" accounts of
the rule of law, as these are limited to a familiar set of
formal-procedural desiderata that are not intended to be exhaustive of
the desiderata applicable to the assessment of law (Franck 1995;
Chesterman 2008). These desiderata include the following: that legal
norms be expressed in general, prospective, and clear terms, that they
are relatively stable over time and do not issue in conflicting
demands or demands that cannot be feasibly complied with, that
officials (judges, bureaucrats, police etc) charged with applying them
do so consistently and in accordance with their meaning, and so on
(Raz 1979: 214-8; Fuller, 1964: 33-41). These
formal-procedural requirements are usually thought to require certain
institutional arrangements for their effective realization, such as an
independent judiciary and access to professional legal advice.



While proponents of the thin theory admit that compliance with the
rule of law, so understood, is compatible with extreme injustice, it
nonetheless has inherent value, an important way of respecting those
subject to laws as rational agents who are given the opportunity to
take legal norms into account in their practical deliberation prior to
reaching a decision (Fuller 1964: 162; Raz 1979: 221; Finnis 2011:
273). In this way, it acts as a significant, but not comprehensive,
limitation on certain forms of arbitrary official power. Moreover,
some requirements of the rule of law, such as the prohibition of
retrospective punishment, seem to capture basic demands of justice.
Finally, the rule of law has various kinds of instrumental value, such
as helping achieve social goods including economic efficiency (by
fostering a predictable environment for economic decision-making) and
democratic governance (by ensuring, for example, that laws enacted
democratically are effectively applied according to their terms).



But even on a thin interpretation of the rule of law, there are
problems about its applicability to international law. Jeremy Waldron
has highlighted two major disanalogies between domestic and
international law that bear on the applicability of the rule of law
ideal in the case of the latter (Waldron 2011). The first is that,
unlike ordinary citizens in domestic legal systems who are contrasted
with officials, states in the international legal order are both the
subjects of international law and its officials (its creators, e.g.,
via treaty-making and processes of customary international law, and
its enforcers, e.g., via countermeasures). The second disanalogy is
that, unlike individual human beings, states do not have inherent
moral value; in particular, their freedom seems to be valuable only
insofar as it serves the interests of individual human beings. One
practical upshot of both of these disanalogies is that we cannot
readily proceed on the assumption, which is justified in the domestic
case in relation to the conduct of individuals, that state conduct
should be free of official interference unless clearly circumscribed
by law. One response to Waldron's first disanalogy is to say
that it is a matter of degree; even in a domestic legal order,
compliance with the rule of law will depend upon the attitudes and
habits of ordinary citizens in sustaining a rule of law respecting
culture. Meanwhile, one response to the second disanalogy is to argue
that although state autonomy is not inherently valuable, it acquires
value derivatively, as a means of protecting the autonomy of
individuals and groups within states (Pavel 2021: 346).



Finally, some argue that the enormous power disparities among states,
combined with the absence of centralized and effective enforcement
mechanisms, pose a systemic obstacle to the realization of the rule of
law (Posner 2009). It is an open question to what extent the
proliferation of discrete international legal regimes, e.g., relating
to trade, human rights, with associated adjudicatory mechanisms, e.g.,
World Trade Organization, regional human rights courts such as the
European Court of Human Rights or the Inter-American Court of Human
Rights, begin to address this problem.



Even if we admit that the rule of law applies to international law,
there is a further question regarding the extent to which
international law, in its current manifestation, complies with it
(Lefkowitz 2020: 90-97). This is an immense topic, so it can
only be dealt with very cursorily here by reference to three problem
areas pertaining to sources of law (custom), United Nations
institutions (the UN Security Council), and one domain of law in which
rule of law considerations have occasioned much controversy
(international criminal law).


### 5.3 Custom



Many critics allege that customary international law, with its
reliance on vaguely-specified levels and combinations of state
practice and *opinio juris,* renders the existence and content
of international legal norms highly indeterminate, thereby violating
the rule of law demand for notice and clarity (Goldsmith & Posner
2005). Moreover, the process of reforming customary international law
over time, which may involve states contravening existing customary
norms in order to give rise to new norms, violates the rule of law
requirement of congruence between law and official behaviour. Such
criticisms have spurred efforts to construct accounts of the formation
of customary international law that secure greater determinacy and
that dispense with the need for violating existing custom in order to
make new custom. But an alternative view is that greater fidelity to
the rule of law requires that treaty law regimes should increasingly
displace customary law (For contrasting views, see Bradley (ed.)
2016).


### 5.4 UN Security Council Resolutions



The United Nations General Assembly's Declaration on the Rule of
Law at the National and International Levels stipulates that



> 
> 
> the rule of law applies to all States equally, and to international
> organizations, including the United Nations and its principal organs.
> (UN GA Res 67/1, 24 September 2012, para 2)
> 
> 
> 



But there are notorious difficulties about the extent to which the UN
Security Council, in particular, has complied with the international
rule of law during the post-Cold War period when it has made
resolutions "to maintain or restore international peace and
security" under Chapter VII of the UN Charter (see Crawford
2014: Ch.XIII). The worry is that exercises of this power--e.g.,
to impose embargoes, authorize peace-keeping operations or military
intervention, set up new rules on topics such as terrorism, establish
criminal tribunals etc--is insufficiently regulated by law. Even
if an argument can be made that the Security Council is bound not only
by the UN Charter, but also by international law generally, a serious
question remains as to the means of securing its compliance with such
law. Is it enough that the legal validity of its resolutions is in
principle justiciable if the issue properly arises in litigation
before a court or tribunal? (ICJ 1971: p. 45, para. 88) Or should the
ICJ be given the general power to review UNSC resolutions as leading
scholars have suggested (Franck 1995; Crawford & Marks 1998)?
Ultimately, there is an issue of ensuring adequate respect for the
rule of law while giving the UN Security Council the flexibility to
respond effectively to any "threat to the peace, breach of the
peace, or act of aggression" (Art 39 UN Charter).


### 5.5 International Criminal Law



As a newly emergent area of international law, one main concern about
international criminal law's respect for the rule of law has
traditionally focused on whether it complies with the demand that
individuals should have fair warning that certain kinds of behaviour
are criminally prohibited and attract liability to punishment. A
dramatic illustration of this problem is the Nuremburg Trials, where
it was questionable whether all of the grievous wrongs for which Nazi
defendants were tried were in fact criminally prohibited by
international law at the time they were committed (Kelsen 1947: 171).
One response to these concerns is to argue that the wrongs in question
were so obviously evil, and the subjection of their perpetrators to
criminal trial and punishment so clearly justified and predictable,
that the obligation to give due notice did not have great weight
(Luban 2010: 583-587). To a significant degree, this problem has
now been addressed, both as a result of the Rome Statute of the
International Criminal Court, which defines the crimes of genocide,
crimes against humanity, war crimes, and the crime of aggression, and
assigns jurisdiction to the International Criminal Court, and as a
result of the evolution of counterpart norms in customary
international law.



Yet a serious problem remains with another component of the rule of
law, which is the congruence between official conduct and legal norms,
ensuring that like cases are treated alike and therefore that all
prospective defendants are equal before the law. This is the scandal
that the defendants who stand trial for international crimes
overwhelmingly come from the Global South rather than from the
powerful North Atlantic democracies. This is deeply troubling, given
the great importance that the rule of law is typically thought to
possess in the criminal law context, and has led even one expert to
speak of the "demise of international criminal law" (Osiel
2014
 [Other Internet Resources]).
 One can imagine various responses to this concern. One is that the
absence of a centralized global state whose arbitrary exercise of
massive power urgently needs to be reined in by law greatly diminishes
this rule of law blemish in the international case (Luban 2010:
583-587). Another is a more pragmatic response, according to
which the edifice of international criminal justice must be patiently
built up, brick by brick, and that geographically skewed prosecutions
have their value, despite the cost incurred in transgressing the rule
of law, as they are part of an ongoing effort to make international
criminal law more generally effective over time.