While concern about public irrationality and antiscientific movements is not new, the increasing power of right-wing populist movements that promote distrust of expertise and of scientific institutions gives such concerns a new context. Experience with classic pseudosciences such as creationism, and the long-running efforts by defenders of science to oppose such pseudosciences, may also help us understand today’s post-truth populism. The politics of creationism and science education in the United States and in Turkey does not, however, suggest easy answers. Moreover, there are important features of politics in liberal democracies that drive a populist backlash, which makes it counterproductive for defenders of science to call for deference to all forms of expertise claimed by professionals. There is a danger that the rhetoric of reason that is used to defend science will become part of a more general apologetics for an unsustainable status quo.