WASHINGTON — Fleeing from the police in a car is a violent felony that can subject criminals to mandatory 15-year prison terms, the Supreme Court ruled on Thursday in a 6-to-3 decision.

The decision was the court’s fourth encounter since 2007 with a phrase in a federal law, the Armed Career Criminal Act. Under the law, convicted felons found with guns face a maximum sentence of 10 years. But those with three convictions for violent felonies are subject to a 15-year mandatory minimum sentence.

The law defines violent felonies as including burglary, arson and other “conduct that presents a serious potential risk of physical injury to another.” The defendant in the case Thursday, Marcus Sykes, pleaded guilty to having a gun in violation of the federal law, and it was undisputed that he had twice committed violent felonies, by robbing a man of his wristwatch and a woman of her purse.

The question in the case was whether a third conviction under Indiana law for fleeing from the police in a car was also a violent felony. Mr. Sykes’s flight was dangerous, Justice Anthony M. Kennedy wrote for the majority. “Sykes wove through traffic, drove on the wrong side of the road and through yards containing bystanders, passed through a fence and struck the rear of a house,” Justice Kennedy wrote.