The Constitution of the United States has been an extraordinarily influential document. In the centuries since it was written, most of the world's countries, including countries that are hostile to the United States and to the idea of subordinating political authority to law, have enacted constitutions of their own. American political movements, libertarianism among them, take the American constitution as a fixed point around which all political discourse revolves.
But the Constitution these movements are reading — and I include libertarians in this — is not necessarily the actual document. Often enough it's their own idea of what that document is, or ought to be. An informed discussion of American government and politics would do better to take the actual document as a reference point, if only to see how far the current political system has departed from it.
The great failing of libertarians is an excessively theoretical reading of the Constitution. From time to time the libertarian movement has put forth draft "new constitutions" for hypothetical new countries — either countries to be built on some remote reef or island, or in outer space, or countries that exist only as ethical ideals. Characteristically, these documents read like mathematical systems, or Spinoza's Ethics, with its famous more geometrico, applying the deductive style of Euclid to ethics. Libertarians would like the Constitution to be a system of axioms, from which all politics and law could be derived by deductive logic; and they would like it to require no justification except reason and abstract political theory.
In fact, the Constitution is not such an abstract work. It lacks many statements of principles that would be necessary for a system of political axioms, and it contains many things that are far too specific for such a work. That's not to say it's not a rational document; but its rationality is of a different kind. Knowing what kind of rationality it embodied will help us read it with better understanding.
Libertarians, in particular, tend to read the Constitution as a legal agreement among the people of the thirteen states, establishing certain institutions to whose authority they are to submit themselves — a social contract, of the sort that figures in the philosophical works of Hobbes, Locke, and Rousseau. Ever since the 19th Century anarchist Lysander Spooner published No Treason: The Constitution of No Authority, libertarians have known how to point out how far the Constitution falls short of the normal standards of contractual law, and how little meaning it has to say that any person in the United States has consented to be bound by it. Randy L. Barnett's recent study of the Constitution starts out by reexamining the entire issue and concluding that the Constitution cannot be read as based on consent.
This text in fact calls not merely for consent, but for unanimous consent. The Constitution applies to the states that have ratified it, but not to the states that have not. (In fact, from 1787 through 1790, all thirteen states ratified it, followed in 1791 by Vermont.) But the consenting entities are the states, not the people as individuals. The authors of the Constitution had no special concern with rebuilding political authority from its ultimate foundations, as a philosopher might wish to do. They took the states as going concerns, accepted them as legitimate, and built a superstructure upon them. The preamble may speak of "we the people", but the operative clauses mostly leave them out.
What is this superstructure meant to do? For that, we can look at the powers that it grants. The substance of the Constitution begins with a discussion of legislative powers, with no definition of what legislation is and no justification of the specific powers to be granted. The legislative body is empowered to facilitate trade between the states and with other nations; to carry on military enterprises and diplomatic relations; and to pass laws, collect taxes, and do other things that are necessary to the functions of the new federal government. It is not granted any broader powers, and it is pointedly denied some powers, including the power to create an aristocracy and the power to impose direct taxes that are not in proportion to the population. This last point is extraordinary: Congress is restricted, not merely to collecting taxes from the people in proportion to their incomes or wealth, but to collecting the same amount per person (averaged over the population of each state). Only Murray Rothbard, among recent libertarians, went so far as to suggest that the closest thing to a just tax that could be attained would be a head tax.
Conversely, the states are required to give up certain specific powers, which means that they formerly had those powers and would still have them if not for the Constitution. Some of these are powers that are also forbidden to Congress, such as creating an aristocracy; others are granted to Congress and thus taken out of the hands of the states, such as coining money and waging war.
The Constitution may be, as a later article says, "the supreme law of the land", but that law is not needed to bring the states into being, or to entitle them to exist — as would seem to be necessary if all proper law and all political institutions had to be deduced from the principles of the Constitution. The states are already there. What the Constitution is doing is not creating them, or remaking them, but establishing a binding agreement among them to do certain things as a joint enterprise. It's a set of engineering specifications for a certain mechanism: a device for the states to have a common economy, rather than thirteen smaller economies, or fifty; and a provision for the defense of that economy through military and naval forces.
To support this common economy, Article IV goes on to place all citizens of the various states in a common legal framework. States are not allowed to refuse to turn over offenders to the judicial systems of other states, or to deny the rights of the people of other states, or to disregard the legal and judicial decisions made in other states. Just as there is to be one market, there is to be one legal system. The same article requires every state to have a republican form of government, complementing the prohibition against any state setting up an aristocracy.
In these last points, the Constitution indirectly addresses the issue of consent and of "we the people". By providing that state government is to be republican and not aristocratic, and also be providing that all citizens shall enjoy "privileges and immunities", the Constitution seeks to ensure that state governments rest on more than superior force. In effect, it seeks to guarantee its own legitimacy by requiring that all the entities whose agreement brings it into being are themselves legitimate.
The source of the various privileges and immunities, and of the broader legal principles in terms of which the Constitution is to be interpreted, is the common law. The various state governments all operated according to the common law, with differences of detail. The fact that the Constitution is not meant to establish an entire legal, political, or social order is nowhere more evident than in the fact that it does not define such key concepts as property or contract, but assumes that they are already understood. And so they were: the common law defined them.
The common law of England was not originally created by deductive reasoning; it was a series of solutions to problems and disputes worked out by judges. But certain recurring themes ran through all those solutions, including the protection of legally defined rights. When the authors of the Constitution referred to "life, liberty, and property", they had in mind the specific ways those concepts were implemented in the common law. The state governments themselves enforced versions of the common law; the Constitution was an agreement among those governments, made by the same kind of methods that the common law relied on. The framework of law and rights was already understood. The Constitution did not create or define those rights; its validity presupposed the legal framework of individual rights. It was a set of specifications for an instrumentality that would protect those rights, and ensure that different states did not get into conflicts over different versions of those rights. Bringing different laws into harmony might change specific laws, but it could not invalidate the basic structure.
In the debates that followed the proposal of the Constitution, a recurring theme was the demand for a Bill of Rights. It's often recalled, even now, that many people opposed its passage, arguing that the Constitution didn't give Congress the power to take away any rights, and that prohibiting it from taking away certain specific rights would suggest that it might take away others. The Ninth Amendment attempted to address this, by forbidding Congress to deny or disparage rights retained by the people.
Remember that the Constitution was a working document. Its reference to "rights" wasn't about abstract, theoretical rights. It wasn't meant to suggest that the definition of rights in the Constitution itself was what brought them into being. In fact, that interpretation was explicitly rejected. Where did those rights exist, then? In the laws and institutions of the existing states, under their common republican form of government. They are already in the Constitution, as the same "privileges and immunities" that states are required to respect. In fact, they existed in the common law of England, with which all the lawyers who sat in Congress were intimately familiar.
And that's the weakness of libertarian proposals for ideal new constitutions, to be enacted as the first step in creating a new community. If the community does not already have a common sense of what is legal and illegal, no constitution can give it one. Viable law exists as part of the life of a community. Rights exist when they are embodied in specific laws. Making a constitution requires not just agreement on abstract self-evident truths — history shows how easily people who agree on abstractions can fall into murderous conflicts — but agreement on supporting a functioning organization.
This emphasis on practicality, rather than abstract theory, shows up in the Constitution's treatment of religion. Most discussions of this emphasize the First Amendment, with its provisions about church and state and the free exercise of religion. But a more basic statement can be found in Article II, which provides that the president must swear or affirm that he will uphold the Constitution, and in Article VI, which calls for the same oath or affirmation from all officers of the United States and the several states, and prohibits a religious test for holding public office. The significance of the provision for affirmation is easily missed. Even today, prospective jurors are asked to take an oath to perform their duties, and that oath is worded religiously; but those who choose not to take a religious oath are instead asked to perform an affirmation. The Constitution specifically provides that the obligation of public officers need not rest on religious conviction. The Declaration of Independence may cite "the laws of nature and of nature's God", but this kind of philosophical theorizing about the origin of rights and duties is not part of the Constitution. For its purposes, all that matters is that public officers are willing to commit themselves to it.
All of this has changed in many ways, both through amendment of the Constitution, and through judicial interpretation of it. The basic idea that government itself must obey the law still survives; at times it seems that little else remains. But if we wish to understand the original document, we need to read it as a grant of specific powers for specific purposes. The Constitution survives because it was a practical document. Reading it looking for theorems is a mistake; reading it looking for intelligent engineering reveals its essential nature.