1. Profecto utrumque verè dictum est,

2. Homo homini Deus, & Homo homini Lupus.

3. Illud si concives inter se; Hoc, si civitates comparemus.

4. (Hobbes, De Cive)

For most political theorists and historians of political thought, Thomas Hobbes was the ‘first . . . modern theorist of the sovereign state’. This was the state as sovereign over its subjects rather than as a sovereign among sovereigns. The balance of Hobbes’s own writings justified this focus on the internal dimension of the state. Hobbes had much less to say about the relations between states than many scholars – particularly theorists of international relations – would like him to have said. In comparison with his treatment of the domestic powers and rights of the sovereign, his reflections on the law of nations, on the rights of states as international actors and on the behaviour of states in relation to one another were scattered and terse. For this reason, students of Hobbes’s political theory have generally seen his international theory as marginal to the central concerns of his civil science: ‘The external relations of Leviathan are for them on the fringe of Hobbes’ theory.’

The relative silence of Hobbes and of his philosophical commentators on this matter contrasts starkly with his canonical position among the founding fathers of international thought: ‘No student of international relations theory, it seems, can afford to disregard Hobbes’s contribution to that field.’ Within the conventional typologies of international relations theory, Hobbes stands between Hugo Grotius and Immanuel Kant as the presiding genius of one of three major theoretical traditions: the Hobbesian ‘Realist’ theory of international anarchy, the Grotian ‘Rationalist’ theory of international solidarity and the Kantian ‘Revolutionist’ theory of international society. There is clearly a problem here for historians, political theorists and international relations theorists alike. If Hobbes’s contribution to international thought was so fundamental, how could it have been overlooked for so long? And how did he come to be accepted as a foundational figure in the history of international thought if his reflections on the subject were so meagre?