A federal law allows a district court to civilly detain a mentally ill, sexually dangerous federal prisoner beyond the end of her sentence upon a showing by clear and convincing evidence that the inmate (1) “‘engaged or attempted to engage in sexually violent conduct or child molestation,” (2) currently “suffers from a serious mental illness, abnormality, or disorder,” and (3) is “sexually dangerous to others” as a result of the illness. 18 U.S.C. § 4248. The statute guarantees the inmate an attorney, a hearing, and other procedural protections. The federal government must turn the inmate over to the state where she was tried or domiciled if the state will accept her. In 2006, civil commitment proceedings were instituted against Grayson Comstock, Jr. and four other federal inmates (plaintiffs). The inmates had pleaded guilty to crimes involving child pornography and sexual abuse of a minor. The plaintiffs moved to dismiss, arguing that the statute violated the Double Jeopardy Clause, the Ex Post Facto Clause, the Sixth and Eighth Amendments, and the Equal Protection Clause. The district court dismissed on the grounds that (1) commitment required proof beyond a reasonable doubt and (2) Congress had exceeded its authority. The government appealed. The court of appeals affirmed based on the lack of congressional authority. The government petitioned the United States Supreme Court for certiorari to review the limited question of Congress’s authority to enact the statute under Article I, § 8 of the Constitution, which was granted.