I really should read the decision before saying a whole lot but my first impression is that this is incredibly alarming:
In a broad endorsement of federal power, the Supreme Court on Monday ruled that Congress has the authority under the Constitution to allow the continued confinement of some sex offenders after they have completed their criminal sentences.
Prisoner: “Today is the day my sentence is complete!”
Government: “Today is the day we start keeping you in prison without due process and ex post facto increase the penalty as long as we feel like it.”
[H/T to Chet from work.]