A 2010 federal law that restructured the U.S. health insurance system by requiring most Americans to obtain coverage, expanding eligibility for a joint federal–state public insurance program, and creating subsidized online marketplaces and rules to limit insurer practices. Its constitutionality was largely upheld by the Supreme Court in NFIB v. Sebelius (2012) under Congress’s taxing power, producing lasting changes in federalism, the role of the national government in social policy, and partisan debate over health-care policy.