:This essay defends deliberative democracy by reviving a largely forgotten idea of corruption, which I call “cognitive corruption”—the distortion of judgment. I analyze different versions of this idea in the work of Machiavelli, Hobbes, Bentham, and Mill. Historical analysis also helps me rethink orthodox notions of corruption in two ways: I define corruption in terms of public duty rather than public office, and I argue that corruption can be both by and for political parties. In deliberative democracy, citizens can take (...) off their party hats and may be more influenced by the force of the better argument than in party democracy. (shrink)