Offensive realism is a structural theory in international relations that belongs to the neorealist school of thought and was put forward by the political scholar John Mearsheimer in response to defensive realism. Offensive realism holds that the anarchic nature of the international system is responsible for the promotion of aggressive state behavior in international politics. The theory fundamentally differs from defensive realism by depicting great powers as power-maximizing revisionists privileging buck-passing and self-promotion over balancing strategies in their consistent aim to dominate the international system. The theory brings important alternative contributions for the study and understanding of international relations but remains the subject of criticism. Theoretical origins Offensive realism is a prominent and important theory of international relations belonging to the realist school of thought, which includes various sub-trends characterised by the different perspectives of representative scholars such as Robert Gilpin, Randall Schweller, Eric J. Labs and Fareed Zakaria. Yet, to date, the most important variant of offensive neorealism is that of John J. Mearsheimer as fully developed in his book The Tragedy of Great Power Politics. While Mearsheimer's offensive neorealism theory does reiterate and build on certain assumptions elaborated by classical realists, it departs completely from this branch by using positivism as a philosophy of science and by adding a system-centric approach to the study of state behaviour in international politics based on the structure of the international system. Accordingly, his offensive neorealism pertains to the sub-branch of neorealism alongside other structural theories such as defensive realism. Main tenets The theory is grounded on five central assumptions similar to the ones that lie at the core of Kenneth Waltz's defensive neorealism. These are: Great powers are the main actors in world politics and the international system is anarchical All states possess some offensive military capability States can never be certain of the intentions of other states States have survival as their primary goal States are rational actors, capable of coming up with sound strategies that maximize their prospects for survival Like defensive neorealism, offensive realism posits an anarchic international system in which rational great powers uncertain of other states' intentions and capable of military offensive strive to survive. Although initially developed from similar propositions to those of defensive neorealism, Mearsheimer's offensive neorealism advances drastically different predictions regarding great power behaviour in international politics. Mainly, it diverges from defensive neorealism in regards to the accumulation of power a state needs