Kevin de Leon, California state Senate president pro tem and Democratic candidate for the U.S. Senate, speaks during an election party in Los Angeles, June 5, 2018.
Kevin de Leon, California state Senate president pro tem and Democratic candidate for the U.S. Senate, speaks during an election party in Los Angeles, June 5, 2018.

Democrats in California, the most populous U.S. state, appear to be on track after Tuesday's primary elections to win slots on November's general election ballots in key congressional districts, a major factor in the party's effort to take control of the House of Representatives in Washington.

California has a unique "jungle primary" election system in which the top two finishers, regardless of party, advance to runoffs five months from now. With multiple Democrats running in several congressional districts, party officials had feared Democrats could split their vote in the primary, leaving two Republicans on November ballots.

But even as late vote counting continues, and could for several days, Democrats appear to be poised to claim slots, at least as second-place finishers behind Republicans, on nearly every House ballot in the western state, including in some congressional districts won by Republicans two years ago even as Democrat Hillary Clinton easily outpolled Republican Donald Trump in the presidential race. 

Democratic Lt. Gov. Gavin Newsom, right, speaks at
Democratic Lt. Gov. Gavin Newsom, right, speaks at his gubernatorial campaign's primary night watch party next to his wife Jennifer Siebel Newsom in San Francisco, June 5, 2018.

Democrats are looking to the liberal state of California, where opposition to Trump is pronounced, to provide some of the 23-seat pickup they would need to wrest control of the House from Republicans.

Republicans in California avoided their own political lockout in the gubernatorial race, when Republican businessman John Cox finished second in the 27-candidate field. But he starts as a heavy underdog in the race for governor against the front-runner in Tuesday's balloting, Democratic Lieutenant Governor Gavin Newsom, a former mayor of San Francisco.

Trump tweeted his support for Cox on election day, which quickly turned into the focal point for the upcoming contest between Newsom and Cox, one of whom will succeed long-term Governor Jerry Brown.

Republican gubernatorial candidate John Cox speaks
Republican gubernatorial candidate John Cox speaks at his election night headquarters after placing second in the California primary in San Diego, California, June 5, 2018.

"We're engaged in an epic battle, and it looks like voters will have a real choice this November between a governor who's going to stand up to Donald Trump and a foot soldier in his war on California," Newsom said.

The Democrat unveiled a new slogan for his candidacy: "Resistance with results."

Cox retorted, "It wasn't Donald Trump who made California the highest tax state in the country. It was Gavin Newsom and the Democrats."

In other California voting, Democrat Dianne Feinstein, 84, is one step closer to re-election to a sixth term in the U.S. Senate, easily outpolling Democratic state Senator Kevin de Leon, who is 51. They will now face each other in the November voting.

FILE - U.S. Sen. Dianne Feinstein, D-Calif., speak
FILE - U.S. Sen. Dianne Feinstein, D-Calif., speaks at a gathering for Planned Parenthood in Sacramento, Calif., May 31, 2018.

Seven other states held primary elections Tuesday.

In the southern state of Alabama, Republican Congresswoman Martha Roby was forced into a primary runoff against Democrat-turned-Republican Bobby Bright. Opponents had said Roby was insufficiently supportive of Trump because she had made critical comments about him during his 2016 presidential campaign.

In the western state of Montana, Republican voters picked state auditor Matt Rosendale to run against incumbent Democratic Senator Jon Tester, a key target of Trump as Republicans try to add to their narrow 51-49 majority in the Senate.