The distinction between ideal and nonideal theory is an important methodological concern in contemporary political theory. At issue is the extent to which political theorizing is a practical endeavor and, consequently, the extent to which real-world facts should either be factored into political theorizing or else be assumed away. The distinction between ideal theory and nonideal theory was first introduced by John Rawls in his classic A Theory of Justice. Rawls’s ideal theory is an account of the society we should aim for, given certain facts about human nature and possible social institutions, and involves two central assumptions. First, it assumes full compliance of relevant agents with the demands of justice. Second, it assumes that historical and natural conditions of society are reasonably favorable. These two assumptions are individually necessary and jointly sufficient for his ideal theory. For Rawls, nonideal theory primarily addresses the question of how the ideal might be achieved in practical, permissible steps, from the actual, partially just society we occupy. The account of ideal and nonideal theory advanced by Rawls has been subject to criticism from different directions. Amartya Sen accepts Rawls’s distinction between ideal and nonideal theory but argues that Rawlsian-style nonideal theory is too ideal. Given the many and severe injustices we face we do not need to know what ideal (or “transcendental”) justice looks like; our focus should not be on how to transition toward this ideal. Instead, the advancement of justice requires a comparative judgment which ranks possible policies in terms of being more or less just than the status quo. G. A. Cohen, by contrast, argues that Rawlsian-style ideal theory is not really ideal theory as such, but instead principles for regulating society. Our beliefs about normative principles should, ultimately, be insensitive to matters of empirical fact; genuine ideal theory is a form of moral epistemology (an exercise of identifying normative truths).