Supreme Court strikes down ACA Medicaid expansion mandate as unconstitutionally coercive in NFIB v. Sebelius

The Supreme Court ruled in National Federation of Independent Business v. Sebelius that Congress had exceeded its spending power by threatening to strip all existing Medicaid funding from states that refused to expand Medicaid under the Affordable Care Act. Chief Justice John Roberts, writing for a fractured majority, held that withdrawing existing funding from states that chose not to participate in the expansion held "a gun to the head" of state governments — coercive rather than merely conditional. The ruling was the first time the Court treated the coercion doctrine as an actual constitutional limit rather than a theoretical possibility, giving states a new legal weapon against federal leverage over their policies.