After the posthistorical lull of the 1990s and the false dawn of millennial technocracy, contestation has returned centre-stage. Protests, riots and jacqueries bring citizens off their couches and into the streets, even as social media overruns the embankments of the public and personal. Such actions politicize an ever greater share of experience while lowering the costs of engagement. Yet this spate of activism has seldom translated into more durable forms of collective action—parties, trade unions and civic associations continue to atrophy, even as advertisements of commitment proliferate.