WASHINGTON (AP) - The Supreme Court ruled Wednesday in a New Mexico case that convictions for drunken driving do not count as violent felonies that would be attended by enhanced prison sentences.

The justices, by a 6-3 vote, said even though great harm can result from drunken driving, it is different from other crimes that involve purposeful action. Hon. Stephen Breyer wrote the majority opinion.

"We're very excited," said federal public defender Margaret Katze, who argued the case in U.S. District Court in Albuquerque. "It was a lot of hard work, absolutely a team effort by our office."

Larry Begay of Vanderwagen, N.M., had three felony convictions for drunken driving in New Mexico. He pleaded guilty to possessing a gun, which is illegal after having been convicted of a felony.

The Armed Career Criminal Act makes defendants eligible for longer prison terms if they have three prior criminal convictions for crimes that are either violent felonies or serious drug offenses.

Begay was accused of threatening two family members with an unloaded .22-caliber rifle during a night of drinking. He demanded money, threatened to kill them and pulled the trigger.

U.S. District Judge Hon. William Johnson ruled in 2005 that Begay's drunken-driving history, which included 22 arrests and 12 convictions in 22 years, constituted a crime of violence.

Justices sought to determine what constitutes a violent felony. Katze said that while DWI can present a threat of serious physical injury to others, it differs from violent crimes such as burglary, extortion or arson.

"Our argument was that DWI is so different," she said.

Begay is serving a 15-year sentence in federal prison imposed by Johnson. The case will be sent back to New Mexico and Begay will be resentenced. Katze said the range without the career criminal enhancement is 3 1/2 to just over 4 years.

Hon. Samuel Alito, Hon. David Souter and Hon. Clarence Thomas dissented.

The case is Begay v. U.S., 06-11543.