Newsom says he won't run for Senate

California Lt. Gov. Gavin Newsom says he won't run for the open U.S. Senate seat created by Democratic Sen. Barbara Boxer's retirement next year.

On his Facebook page, Newsom says it's better to be candid than coy, and while he's humbled by widespread encouragement to seek federal office, he has unfinished work in the state of California -- not Washington, D.C.

Newsom would have been considered a top contender in a race that's also drawing interest from other Democratic heavyweights.  Others who say they are considering running for the seat include former Los Angeles Mayor Antonio Villaraigosa and Tom Steyer, a retired San Francisco hedge fund billionaire who sought to make climate change an issue in the midterm elections.

Newsom previously served eight years as mayor of San Francisco.