ABSTRACT
This chapter claims that the most enlightening aspect of Reinhold Niebuhr's reflections on American foreign policy, which were grounded on his IR theory and on the emphasis on existential anxiety rather than Hobbesian fear, was in how he anticipated the challenges confronting the United States as a great power and, later on, as the only superpower in international politics. Niebuhr's ability to characterize the paradoxical nature of America's position in the world as a stranded nation that is at the same time the one capable of bringing change more than any other and yet, for that very reason, unable to resist the systemic pressures of an international system that it has in part created. Niebuhr's critique of Wilsonianism suggests that, just as Stalinism or Nazism were inspired by modern ideals of social emancipation, he was afraid that liberal democracies would mobilize the masses around what where initially democratic ideals but could soon be corrupted into tyrannical forms by populist parties.
