The social movement has become institutionalized as a form of political action. The aim of this article is to evaluate the possibilities presented by this form as a strategy to bring about universal health insurance in the United States. I draw on the work of social movement theorists, on the substantial body of empirical research on health-related social movements, and on relevant comparative work from Canada to develop a template for this evaluation. Using that template I compare the failed campaign for President Bill Clinton's health insurance plan with a recent, more successful campaign in the state of New York. I conclude that the keys to success are, first, a broad-based coalition that combines an ideologically and/or grievance-motivated grass roots with financially and politically well-endowed mainstream organizations; second, a “master frame” that resonates with the American people; and, third, a political window of opportunity. The prospects for such a conjunction are not hopeless, but they are not high.