On Monday, the high court reversed that decision.
Writing for the seven-member majority, Justice Stephen Breyer said Congress’s authority to enact the measure stemmed from the Constitution’s necessary and proper clause.
“The statute is a ‘necessary and proper’ means of exercising the federal authority that permits Congress to create federal criminal laws, to punish their violation, to imprison violators, to provide appropriately for those imprisoned, and to maintain the security of those who are not imprisoned but who may be affected by the federal imprisonment of others,” Justice Breyer wrote.
Breyer cautioned that his decision should not be read as granting to Congress a general police power, “which the Founders denied the National Government and reposed in the States.”
Instead, Breyer compared the statute to federal efforts to prevent the spread of disease from released prisoners to the general population.
“If a federal prisoner is infected with a communicable disease that threatens others, surely it would be ‘necessary and proper’ for the federal government to take action [and] refuse to release that individual among the general public where he might infect others,” Breyer wrote.
“And if confinement of an individual is a ‘necessary and proper’ thing to do,” he said, “then how could it not be similarly ‘necessary and proper’ to confine an individual whose mental illness threatens others to the same degree?”
In a dissent, Justice Clarence Thomas said Breyer’s opinion “comes perilously close to transforming the necessary and proper clause into a basis for the national police power that we always have rejected.”
The necessary and proper clause authorizes Congress to enact only those laws that facilitate federal powers enumerated in the Constitution, he said. But Section 4248 is unrelated to any enumerated powers, Justice Thomas said in his dissent, which was joined by Justice Antonin Scalia.