In political systems defined by legitimate opposition, those who hold power allow their rivals to peacefully challenge and displace them, and those who have lost power do not seek to sabotage the winners. Legitimate opposition came under assault at the American capitol on January 6, 2021, and is menaced by populists and autocrats across the globe.

Alexander Kirshner provides the first sustained theory of legitimate opposition since the Cold War. On the orthodox view, democracy is lost when legitimate opposition is subverted. But efforts to reconcile opposition with democracy fail to identify the value of the frequently imperfect, unfair, and inegalitarian real-world practice. Marshaling a revisionist reconstruction of opposition's history, Kirshner provides a new account of opposition's value fit for the twenty-first century and shows why, given the difficult conditions of political life, legitimate opposition is an achievement worth defending.