Democratic candidate Gregory S. Pettis garnered 4,240 votes, or 20 percent of the vote.
In the 40th Senate District, which includes the Imperial Valley, Democrat Denise Moreno Ducheny of San Diego received 30,683 votes; Republican Michael S. Giorgino of Coronado received 23,292 votes; and Libertarian Felix J. Miranda of Chula Vista garnered 182 votes.
All three ran unopposed in the primary and will face each other in the November run-off.
The Democrat-dominated California Legislature may become even more liberal after voters nominated new moderates and liberals in districts where they are likely to win in November.
In a legislative primary widely viewed as having more impact than the general election, ruling Democrats on Tuesday picked up a fresh slate of environment and consumer-minded candidates, especially in the 80-member Assembly.
Republicans, meanwhile, largely elected conservatives rather than moderates for their seats, despite fund-raising efforts by some in the party to support more centrist candidates.
The New Majority PAC, moderate Republicans who offered financial support to at least three candidates, lost all three contests.
Tuesday's results pleased Democratic legislative strategists, who said a gain of several seats by liberals could give them more clout in the Assembly.
‘‘All I wanted was to do what the chambers of commerce and manufacturers have been doing for years when they give money and elect pro-business Democrats,'' said Sen. Sheila Kuehl, D-Santa Monica. ‘‘There was no one on the other side of the chessboard. I think we're doing very well,'' she said.
Kuehl and other legislative liberals backed 13 socially progressive Democratic candidates after suffering narrow defeats last year on privacy and consumer bills.
Nine prevailed in Tuesday's election, including former Berkeley Mayor Loni Hancock, South San Francisco Mayor Gene Mullin and Mountain View Councilwoman Sally Lieber.
‘‘It's sort of one vote at a time,'' Kuehl said. ‘‘You kind of put together a coalition one vote at a time.''
But Republican leaders lamented the Legislature's continued ‘‘leftward drift.''
‘‘I believe the composition of the Legislature is not reflective of the philosophy and expectations of the people,'' said Senate Republican Caucus Chair Charles Poochigian, R-Fresno.
He added that the ‘‘stark contrast'' between candidates and voters will eventually backfire.
‘‘I believe in the long run the Republican party will benefit from the radicalization of the Legislature,'' he said.
One of the Legislature's most competitive races mirrored the liberal trend and widening split between the two parties.
In the 30th Assembly district, San Joaquin Valley voters nominated liberal Democrat Nicole Parra, a congressional district director, with 53 percent of the vote over 25 percent for conservative farmer and Democrat Jim Crettol. In November, Parra will face a conservative Republican businessman, Dean Gardner, who defeated moderate Republican Jerry Salazar 66 to 34 percent on Tuesday.
Salazar had received a $12,000 assist from the New Majority PAC of moderate Republicans seeking to push their party toward the political center.
Another moderate candidate backed by the PAC, Assemblyman Richard Dickerson, R-Redding, lost his bid for a Senate nomination to conservative Assemblyman Sam Aanestad, R-Grass Valley. Aanestad received 56 percent of the vote to Dickerson's 44 percent.
Likewise, Assemblywoman Charlene Zettel, R-Poway, a pro-choice moderate, received 46 percent of the vote in losing to conservative Assemblyman Dennis Hollingsworth, R-Temecula. Hollingsworth, a former legislative director for the Riverside County Farm Bureau, captured 54 percent of the vote.
In another groundbreaking trend, Democratic voters nominated openly gay former Santa Cruz councilman John Laird for one Assembly race and were choosing between two gay activists in another Assembly district — San Francisco Supervisor Mark Leno and former San Francisco Supervisor Harry Britt. If elected in November, they would be the Legislature's first openly gay male members. The Legislature already has four gay women.
Voters also set the stage for a pair of possible political comebacks: Former assemblyman and current state parks director Rusty Areias won the Democratic nomination for a San Joaquin Valley Senate seat with 62 percent of the vote. Former assemblyman, congressman and lieutenant governor Mervyn Dymally, 75, received 52 percent of the vote, heading off a Latino challenger to continue longtime African-American representation of his heavily Democratic South Central Los Angeles Assembly district.