What are the politics of political realism? This paper tries to answer the question by showing the political differences that emerged between the doyens of IR realism theory—Raymond Aron, Hans Morgenthau and George Kennan—during the 1970s. It argues that the Vietnam War and differing perceptions of American military power in the 1970s led these elder statesmen of IR realism theory into myriad political directions. Perhaps the best way to understand the nature of IR realist thought, then, is to focus not just on the theories that inspire political realism, but its diverse political applications, which, in the case of Aron, Morgenthau and Kennan, led to wide-ranging ways of thinking about what the role of the US in the world should be. If we make this move, we would see that Aron, the supposed embodiment of liberal moderation, became by the 1970s the most reactionary or militarist of the elder generation of IR realists.