A unanimous court on Tuesday threw out a mandatory 15-year prison term given to Deondery Chambers, who pleaded guilty to being a felon in possession of a gun. Chambers had three prior convictions, which prosecutors argued and lower courts agreed brought him under the federal Armed Career Criminal Act.

But one of Chambers' convictions was for his "failure to report" for weekend jail stays. The government contended that not showing up for the weekend confinement was akin to an escape and should be treated as a violent crime.

Justice Stephen Breyer rejected that argument in his opinion for the court. Breyer said a report that examined failures to report to prison found no evidence that defendants were more likely to resist arrest and potentially injure law enforcement officers or others.

In a separate opinion, Justice Samuel Alito said the court is called on too often to interpret the career criminal law and suggested that Congress come up with a list of specific crimes that should trigger application of the law.

In a second criminal case, the court unanimously ruled for a Texas prison inmate seeking federal review of his 43-year prison term. The federal appeals court in New Orleans was wrong to find that Carlos Jiminez had missed a deadline for filing his paperwork in federal court, Justice Clarence Thomas said for the court.

The cases are Chambers v. U.S., 06-11206, and Jiminez v. Quarterman, 07-6984.