Jarman and Greer consider how the fragmentation of the U.S. political system acts as a key obstacle to state‐wide universal health insurance coverage. The “paradox of purity” poses a difficult dilemma for reformers: groups with influence among policymakers have a better of chance of seeing their reforms enacted, but to be successful, they must adopt narrower policy goals or accept smaller reforms. Less influential groups are free to “think big,” but have a greatly reduced chance of seeing their goals implemented. Jarman and Greer consider how a social movement for health reform might resolve this paradox. Their chapter analyzes the campaigns for universal health coverage in Pennsylvania and Wisconsin, contrasting the fragmentation of Pennsylvania activists with the coalition‐building techniques developed in Wisconsin to assess how proponents of big ideas can successfully build a support base broad enough to overcome a fragmented U.S. political system.