People tend to be biased and irrational about politics. Should this constrain what our normative theories of democracy can require? David Estlund argues that the answer is ‘no’. He contends that even if such facts show that the requirements of a normative theory are very unlikely to be met, this need not imply that the theory is unduly unrealistic. I argue that the application of Estlund’s argument to political irrationality depends on a false presupposition: mainly, that being rational about politics (...) is something people could easily do if they tried. Since the empirical evidence shows that being rational about politics is actually quite difficult, Estlund’s argument comes up short. Moreover, I argue that the argument cannot plausibly be extended to insulate normative theories of democracy from facts about political irrationality because of the need for constraints of realism to explain the crucial role that appeals to (reasonable) disagreement play within such theories. (shrink)