The United States v. Graydon Earl Comstock, Jr., et al., 2009 case involved a challenge to the constitutionality of a federal law that allows for the civil commitment of individuals already in Federal custody, due to mental illness and sexual dangerousness. The respondents were five men who had been convicted on various federal charges; they completed their prison terms but remained incarcerated because of psychiatric evaluations deeming them sexually dangerous. They argued that this violated their rights under the Due Process Clause and exceeded Congress's powers under Article I of the Constitution. In a 7-2 decision, however, the Supreme Court upheld this provision as constitutional. It ruled that it was within Congress’s authority under its Necessary and Proper Clause power to enact such legislation ensuring public safety from those deemed sexually dangerous even after serving their sentences if they are mentally ill or unable to control behavior.

In the dissenting opinion for United States v. Graydon Earl Comstock, Jr., et al., Justice Thomas, joined by Justice Scalia, argued that the federal government does not have the constitutional authority to civilly commit a mentally ill and sexually dangerous person beyond their prison term under Article I's Necessary and Proper Clause. They contended that this power is reserved for states as it falls outside of enumerated powers granted to Congress in the Constitution. The dissenting justices expressed concern over potential abuse of such broad interpretation of congressional powers which could lead to indefinite detention without trial or conviction. They also criticized majority’s reliance on precedents arguing they were misapplied or irrelevant to this case.