A word should be said about Rousseau’s place among the various schools of international relations theory. Because he wrote so little about international relations directly and because his one published work on the subject is so ambiguous, his views defy simple categorization. His approval of the goal of perpetual peace and dissatisfaction with the continuation of the state of nature among nations would suggest that he belongs among the modern idealists. Yet he evinces none of the modern idealists’ confidence that this goal would be achieved or dissatisfaction remedied. Here, as in other areas of his thought, Rousseau offers much more of a diagnosis of the modern condition than a cure for it.
Hobbes’s contribution to international relations theory is, for all its significance, rather indirect. Hobbes sets out to give an account of the origin and preservation of internal political order. His practical intention is to foster peace, primarily within and only secondarily among nations. Yet Hobbes invites us to draw lessons about international relations from his political theory when he identifies the state that countries find themselves in as the state of nature. The way to Hobbes’s theory of international relations is therefore largely inferential in character.
Thucydides leaves us no doubt that the principal threat to the security of Athenians flowed more from the distinctly flawed working of the empire’s democratic politics, especially its proclivity to promote crowd pleasing demagogues who were short of competence, high ethical standards, or both, than from vengeful Persians or strategically pedestrian Spartans. Political ruin tends to begin and end at home. Students of international relations need to remember this plain warning from the historical record.