The rise of social movements in US legal scholarship is a current response to an age-old problem in progressive legal thought: harnessing law for social change while maintaining a distinction between law and politics. This problem erupted in controversy around the civil rights–era concept of legal liberalism defined by activist courts and lawyers pursuing political reform through law. Contemporary legal scholars have responded by building on social science to develop a new concept—movement liberalism—that assigns leadership of transformative change to social movements to preserve conventional roles for courts and lawyers. Movement liberalism aims to achieve the lost promise of progressive reform, while avoiding critiques of legal activism that have divided scholars for a half-century. Yet rather than resolving the law-politics problem, movement liberalism reproduces long-standing debates, carrying forward critical visions of law that it seeks to transcend.