 Many writers on distributive justice have tended to advocate and defend their particular principles by describing or considering ideal societies operating under them. They have been motivated to do this as an aid to understanding what their principles mean. Unfortunately though, as a result of this practice, some readers and the general public have been misled into believing that discussions of distributive justice are merely exercises in ideal theory—to be dismissed as a past-time of the academic elite rather than as something that is crucially relevant to current political discussion. This misunderstanding is unfortunate because, in the end, the main purpose of distributive justice theory is not to inform decisions about ideal societies but about our societies. To help correct this misunderstanding it is important to acknowledge that there has never been, and never will be, a purely libertarian society or Rawlsian society, or any society whose distribution conforms to one of the proposed principles. Rather than guiding choices between ideal societies, distributive principles are most usefully thought of as providing moral guidance for the choices that each society faces right now. So, for instance, advocates of Rawls’ Difference Principle are most constructively understood as arguing for changes to our basic institutional structures which would improve the lifetime prospects of the least advantaged in society. Other theorists are arguing for changes to bring economic benefits and burdens more in accordance with what people really deserve. Libertarians are arguing that reductions in government intervention in the economy will better respect liberty and/or self-ownership of its citizens. Sometimes a number of the theories may recommend the same changes to our current practices; other times they will diverge. It is best to understand the different theorists, despite the theoretical devices they sometimes employ, to be speaking to what should be done in our society—not about what should be done in some hypothetical society. Of course, ensuring that philosophical principles be effective for the purpose of guiding policy and change in real societies involves important and complex methodological questions. For a review of work specifically addressing this issue, in ideal and nonideal theory, see Zofia Stemplowska and Adam Swift (2012), and Valentini (2012).