"On June 28, 2012, the U.S. Supreme Court issued its decision in the case challenging the Affordable Care Act (ACA). The Court upheld the constitutionality of the ACA's individual mandate, which requires most people to maintain a minimum level of health insurance coverage beginning in 2014. A majority of the Court also found the ACA's Medicaid expansion unconstitutionally coercive of states, while a different majority of the Court held that this issue was fully remedied by limiting the Health and Human Services (HHS) Secretary's enforcement authority. The ruling left the ACA's Medicaid expansion intact in the law, but the practical effect of the Court's decision makes the Medicaid expansion optional for states. This policy brief provides background on the Medicaid program and the legal challenge to the Medicaid expansion under health reform, and summarizes the controlling and dissenting opinions of the Court regarding the Medicaid expansion."