Thucydides' realistic critique of realism

For the last half century foreign policy thinking in the United States has been dominated by the realist school. Part of its prestige has rested on its adherents' ability to trace their intellectual pedigree back to Thucydides. Read carefully, however, Thucydides is a theoretical realist who provides a sharp critique of political realism. He does; support twentieth-century realists' claims about the weakness of justice in international affairs and the dangers of moralism in foreign policy. Yet he doubts that realism can form the basis of a successful foreign policy because the human hopes and moral passions that realism opposes as unreasonable are indelible features of political life. Thucydides even suggests that the very attempt to conduct an unabashedly self-interested foreign policy inevitably risks provoking a self-destructive moralistic or religious backlash.