Several Republican Assembly members were in extremely close contests in their re-election bids as the GOP faces an uphill battle to hold onto left-leaning districts and prevent Democrats from grabbing supermajorities in the Assembly and Senate.
Republicans took an early lead in key legislative districts in Tuesday's election, but their leads fizzled as more votes were counted. Tens of thousands of votes remained uncounted early Wednesday.
In the Senate, early results showed the status quo holding.
Democrats are looking to recapture several seats they took from Republicans two years ago, when the GOP had rare success in relatively left-leaning areas of California.
A gain of two Assembly seats and one Senate position would give Democrats the option of raising taxes, suspending legislative rules, passing emergency legislation and overturning vetoes by the governor without any Republican support.
Voters in several strongly Democratic districts were favoring moderate Democrats over more liberal opponents in the state's dominant party.
SUPERMAJORITY HUNT: The balance of power will be determined in a handful of Republican-held districts in Orange County, the Inland Empire and the East Bay.
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In Assembly races, Democrats focused their efforts on defeating first-term Republicans in districts where the parties are closely matched.
Democrats and their allies poured millions of dollars into efforts to defeat freshman Republican Assembly members Catharine Baker of Dublin, David Hadley of Torrance, Young Kim of Fullerton and Marc Steinorth of Rancho Cucamonga, as well as second-term Republican Eric Linder of Corona.
In early returns, Hadley, Kim and Linder trailed their Democratic rivals.
The parties are also battling over open Assembly seats currently held by Republicans in Santa Clarita and San Luis Obispo. Republicans led in both contests.
In the Senate races, Republicans were leading in their efforts to protect two open seats in the Los Angeles area. The GOP eyed two Democratically controlled seats as potential longshot pickups, though early results showed Democrats ahead in both.
Democrats tried aggressively to link at least five Republican legislative candidates to GOP presidential nominee Donald Trump, unleashing a barrage of television and mail ads - even in races where the Republican has repudiated the party's nominee.
DEMOCRAT VS. DEMOCRAT: While the supermajority hunt will determine how much power Republicans have in Sacramento, an ongoing skirmish between interest groups in the Democratic Party will be significant in determining the ideological makeup of the next Legislature.
In about a dozen contests, moderate Democrats backed by businesses and charter-school interests squared off against more liberal Democrats supported by labor unions and environmental groups. The moderates were ahead in most of them.
The Democrat-on-Democrat races are enabled by California's top-two election system, in which the top finishers in June's primary advance to the general election.
The division between moderate and liberal Democrats has been instrumental in determining the outcome of high-profile legislation, most notably an effort by Senate Democrats to curtail oil use from automobiles by 50 percent, which was killed by Assembly moderates last year.
The oil-reduction mandate has become a central issue in the re-election campaign of Assemblywoman Cheryl Brown of San Bernardino, a moderate Democrat who faced a challenge from the left and was trailing Eloise Gomez Reyes.
The most expensive legislative race is between two Democrats in what became a proxy fight between the California Teachers Association, a powerful union, and charter school advocates. Union-backed Mae Torlakson was trailing moderate Tim Grayson in the race for a vacant Assembly seat in the East Bay.
Former Democratic Assemblyman Raul Bocanegra was leading incumbent Democrat Patty Lopez, D-San Fernando, whom Bocanegra defeated in an upset two years ago.
