California's Democratic Lt. Gov. Gavin Newsom announced on Facebook Monday that he won't seek the Democratic nomination in 2016 to succeed retiring Sen. Barbara Boxer (D-Calif.), avoiding what is expected to be a competitive primary for her seat.
"It's always better to be candid than coy," Newsom wrote. "While I am humbled by the widespread encouragement of so many and hold in the highest esteem those who serve us in federal office, I know that my head and my heart, my young family's future, and our unfinished work all remain firmly in the State of California -- not Washington, D.C."
Newsom, the former mayor of San Francisco, added that he looks forward to helping elect a Democrat to replace Boxer, who announced her retirement last week.
California hasn't had an open Senate seat since 1992, so Boxer's news incited intense speculation as to which of California's major political figures would vie for the nomination.
Newsom had frequently been cited as a top potential Democratic candidate, along with California Attorney General Kamala Harris, former Los Angeles Mayor Antonio Villaraigosa, billionaire hedge-fund manager and environmental activist Tom Steyer and a handful of members of Congress.
Villaraigosa has said he's "seriously considering" a Senate bid. Steyer and Harris haven't yet announced their plans.
There may be other higher-level political vacancies Newsom might fill in the future. The state's other Democratic senator, Dianne Feinstein, may retire in 2018, while Gov. Jerry Brown is term-limited and must step down the same year.
Newsom briefly challenged Brown for the Democratic gubernatorial nomination in 2009 but ultimately withdrew from the race.