Although South America has a long history of pendular swings between authoritarianism and democracy, the region shifted decisively toward democracy in the 1980s, and has largely maintained democratic rule since. Over time, however, the institutional fragilities and social deficits of democratic regimes have left them susceptible to destabilizing forms of social mobilization and political polarization. In that context, authoritarian currents of varied political persuasions have reemerged, on both the left and right flanks of national political orders. In contrast to historical patterns of military coups and revolutionary armed struggle, contemporary manifestations of authoritarianism often compete in the democratic arena and make populist appeals to disenchanted mass publics to circumvent or dismantle the institutional checks and balances of democratic regimes. South America, therefore, despite its achievements during the Third Wave of democratization, is not immune to the patterns of democratic backsliding seen across much of the world in recent times.