Joan Kennedy, the ex-wife of Sen. Edward Kennedy, was arrested on her third drunken driving violation since 1974 and failed to show up in court Wednesday for arraignment.

A judge ordered Kennedy, 55, to show up Thursday in court to surrender her driver's license.Kennedy's arrest Tuesday night comes at a time when her former husband's family is mired in a rape scandal in Florida.

"Obviously we're going to fight it but it depends on the facts of the case," her lawyer, William Sullivan, said.

Asked if Kennedy was being treated for an alcohol problem, Sullivan said, "I'm not saying there is a problem." Kennedy previously had acknowledged that she is a member of Alcoholics Anonymous.

Kennedy was arrested about 9:30 p.m. Tuesday on Interstate 93 by state police who said they saw her car weaving across all three northbound lanes on the expressway south of Boston.