National Federation of Independent Business v. Sebelius

Holding: The Anti-Injunction Act does not bar a challenge to the constitutionality of the Affordable Care Act"s "individual mandate" provision, which requires virtually all Americans to obtain health insurance or pay a penalty, even though the mandate has not yet gone into effect. Although the mandate is not authorized under the Commerce Clause, it is nonetheless a valid exercise of Congress"s power under the Taxing Clause. Finally, the Medicaid expansion provision of the ACA violates the Constitution by threatening states with the loss of their existing Medicaid funding if they decline to comply with the expansion.

Judgment: Affirmed in part and reversed in part, 5-4, in an opinion by Chief Justice Roberts on June 28, 2012. The Anti-Injunction Act does not bar the challenge to the constitutionality of the mandate, and five Justices (the Chief Justice, joined by Justices Ginsburg, Breyer, Sotomayor, and Kagan) agree that the individual mandate is constitutional. Seven Justices (the Chief Justice and Justices Breyer and Kagan, along with Justices Scalia, Kennedy, Thomas, and Alito) agree that the Medicaid expansion violates the Constitution. Justice Ginsburg filed an opinion concurring in part, concurring in the judgment in part and dissenting in part, in which Justice Sotomayor joined, and which Justice Breyer and Kagan joined except as to Medicaid expansion. Justices Scalia, Kennedy, Thomas and Alito filed a dissenting opinion. Justice Thomas filed a dissenting opinion.