Public choice and critical theory constitute two very different and often mutually hostile research traditions. An opportunity for conversation across the two traditions arises inasmuch as public choice has itself demonstrated the incoherence of a politics-in particular, a democratic politics-of unconstrained rational egoism. By deploying an expanded, communicative conception of rationality, critical theory can help move public choice beyond several related impasses. Critical theory benefits from this encounter by gaining content for its currently rather abstract critiques of politics and rationality, and additional insight into the forces conducive to different kinds of rationality. More importantly, political science stands to gain an account of politics more powerful than either tradition can muster by itself.