What explains the success and failure of radical right parties over time and across countries? This article presents a new theory of the radical right that emphasizes its reactive nature and views it as backlash against the political successes of minorities and concessions extracted on their behalf. Unlike approaches that focus on competition between the extreme and mainstream parties, the theory stresses the dynamics between radical right and non-proximate parties that promote minority rights. Most notably, it derives the salience of identity issues in party politics from the polarization of the party system. The theory is tested with a new party-election-level dataset covering all post-communist democracies over the past 20 years. The results provide strong support for the theory and show that the rise and fall of radical right parties is shaped by the politics of minority accommodation.