Marc Hetherington and Jonathan Weiler’s new book re-examines the recent course of American politics. They tell us about how authoritarian politics – especially on the right – have helped give rise to increasing polarization between Republicans and Democrats. This is an important contribution to debate among political scientists about polarization, but deserves a much wider readership. If they are right – and the differences between authoritarians and non-authoritarians are the key factor driving polarized politics – then many of the received wisdoms of the punditocracy are flat out wrong. Right wing columnists like Michael Gerson and Clive Crook, who deplore the increasing extremism of American politics and especially of the left, are missing out on the ways in which right wing politics are increasingly based around authoritarianism and intolerance.