I now turn to contemporary international relations and social science, and exploit my analysis of classical realism to offer a critique of both. I begin with post-Cold War American policy, and examine some of the striking similarities – and important differences – between the United States and Athens. Like mid-fifth-century Athens, Washington gives evidence of breaking free from the traditional constraints which served its broader interests so well in the past. For the United States, these constraints arise from international law, institutional obligations, norms of consultation and policy by consensus among close allies and more general norms associated with the country's frequently proclaimed commitment to a democratic and peaceful world order. For classical realists, this is well-trodden path, down which ancient tyrants, Xerxes' Persia, Periclean Athens, numerous tragic heroes, and many subsequent empires have trod. Success and power breed hubris and now raise the disturbing possibility of America becoming a tragedy.

Current realist theories are blind to this possibility because they are focused on power and external threats. In addition, they tend to equate material capabilities with power and power with influence, ignoring the extent to which the latter is a psychological relationship. Classical realists recognize that the most efficient way to wield influence is through consent, not coercion, and that consent is greatly facilitated by hegemonia and convincing others of the benefits of following one's lead.