Rep. Gary Miller (R-Calif.) will not seek reelection in 2014, he announced Wednesday.
"While there is still a lot of work to be done, it is now time for me to pass the baton," Miller said in a statement. "I will not seek re-election to Congress at the end of this term."
Miller is generally acknowledged to be the most vulnerable member of the House. Redistricting made his district Democratic-leaning, and it went for President Obama by 16 points in 2012. Miller survived, though, by facing another Republicans in the general election under California's unusual top-two primary system.
Rep. Steve Israel (D-N.Y.), who chairs the Democratic Congressional Campaign Committee, called Miller "the most vulnerable Republican in the country" and said it was no surprise that he was planning to leave office.
"He decided that he was on the wrong side and jumped ship because he knows that you cannot continue to defend the indefensible, you cannot continue to defend the wrong priorities in front of the American people," Israel told reporters at the start of the House Democratic policy retreat on Maryland's Eastern shore.
Democrats were favored to win Miller's seat and will likely be heavy favorites now.
The news was first tweeted by California GOP consultant Matt Rexroad.
Miller, 66, has served since 1999. His tenure has been marked by scrutiny over his land deals, which at one point were examined by the FBI.
Several Democrats are running for the seat, including former congressman Joe Baca, Redlands Mayor Pete Aguilar — a favorite of national Democrats — and Eloise Gomez Reyes, who has the backing of the Democratic women's group Emily's List.
In 2011, three of Miller's grandchildren were found in Mexico after going missing for four years. The grandchildren had been with their mother, who fled after she signed their custody over to Miller and his wife.
Miller is the 11th House Republican and 18th House member overall to announce his retirement effective after the 2014 election.
Updated at 6:30 p.m.