In a huge surprise, veteran GOP Rep. Ed Royce, who is termed-out as chair of the House Foreign Affairs Committee, announced on Monday he would not seek re-election. Royce has represented Southern California in the House since 1992, and he's never taken less than 57 percent of the vote. However, Royce's ancestrally red seat, which includes Fullerton and Yorba Linda, did not react well to Trump in 2016, swinging from a 51-47 win for Mitt Romney all the way to 51-43 showing for Hillary Clinton.

Sensing vulnerability, several noteworthy Democrats had already entered the race here, but Royce had amassed a huge $3.5 million war-chest at the end of September, and until now, he had given every indication he was planning to fight it out. In fact, in mid-September, a Royce aide even responded to speculation his boss would bail by saying Royce was "100% running for re-election." Funny how plans can change when the political climate turns bad for your party.

But Republicans still do well in Orange County down the ballot, and they won't give this seat up without a fight. However, Team Red's chances of holding this diverse and well-educated seat are almost certainly a whole lot worse without Royce, unless the top-two primary saves the GOP again. Under California law, all candidates from all parties will compete on one ballot in June, and the two contenders with the most votes will advance to the general election, regardless of party.

It’s therefore distressingly possible that the many Democrats running here will fracture the left-leaning primary vote just enough to allow two Republicans to take first and second place and turn a promising pickup opportunity into an automatic GOP hold. Infamously, this this very disaster unfolded in the nearby 31st District in 2012: Two Republicans advanced to the general election in a seat that ended up backing Obama 57-41, depriving voters of a real choice. Democrats will have to make sure something like this doesn’t happen again.

California's candidate filing deadline is in mid-March, so potential GOP candidates still have a little while to make up their minds. It's possible more Democrats will jump in now that Royce has hit the eject button, but as we said above, the Democratic field is crowded enough as it is. The top contenders are Navy veteran Gil Cisneros, who once won $266 million in a lottery; Andy Thorburn, a businessman and former public school teacher who has highlighted how he was arrested and jailed in the 1970s for participating in an illegal teachers' strike; and Mai-Khanh Tran, who came to the U.S. as a refugee from Vietnam and became a Wall Street analysis and later a pediatrician

Each of these three has thrown a considerable amount of their own money into the race, with Thorburn alone dropping $2 million. Former Commerce Department official Sam Jammal and education consultant Phil Janowicz are also running, though they trail in the money race. The 39th District is located in the Los Angeles media market, where it costs a pretty penny to go on TV and introduce yourself to voters, so both the primary and general election will be expensive. But barring a top-two debacle, this seat, which was already high on Democratic target lists, just shot to almost the very top of the list.