2012 United States Senate election in California

The 2012 United States Senate election in California took place on November 6, 2012, concurrently with the 2012 U.S. presidential election as well as other elections to the United States Senate and House of Representatives and various state and local elections.

The primary election on June 5 took place under California's new blanket primary law, where all candidates appear on the same ballot, regardless of party. In the primary, voters voted for any candidate listed, or write-in any other candidate. The top two finishers—regardless of party—advanced to the general election in November, even if a candidate managed to receive a majority of the votes cast in the June primary. In the primary, less than 15% of the total 2010 census population voted. Incumbent Democratic U.S. Senator Dianne Feinstein announced her intention to run for a fourth full term in April 2011 and finished first in the blanket primary with 49.5% of the vote. The second-place finisher was Republican candidate and autism activist Elizabeth Emken, who won 12.7% of the vote.

Feinstein ultimately defeated Emken in the general election on November 6, winning 62.5% of the vote to Emken's 37.5%. Feinstein's total of 7.86 million popular votes is the most ever received by a candidate for U.S. Senate in American history. For a full decade, Emken was the only Republican candidate to have advanced to a general U.S. Senate election in California, as only Democratic candidates advanced to the general election in 2016 and 2018; however, this streak was broken in 2022.

Democratic Party

 * Dianne Feinstein, incumbent U.S. senator
 * Colleen Shea Fernald
 * David Levitt, computer scientist and engineer
 * Nak Shah, environmental health consultant
 * Diane Stewart, businesswoman
 * Mike Strimling, attorney and former U.S. Peace Corps legal adviser

Republican Party

 * John Boruff, businessman
 * Oscar Alejandro Braun, businessman and rancher
 * Greg Conlon, businessman and CPA
 * Elizabeth Emken, candidate for the 11th congressional district in 2010
 * Rogelio Gloria, U.S. Naval Officer
 * Dan Hughes, businessman
 * Dennis Jackson
 * Dirk Konopik, former congressional aide
 * Donald Krampe
 * Robert Lauten
 * Al Ramirez, businessman
 * Nachum Shifren, rabbi and state senate candidate in 2010
 * Orly Taitz, dentist, Birther movement activist and candidate for California Secretary of State in 2010
 * Rick Williams, business attorney

Libertarian

 * Gail Lightfoot, retired nurse

Peace and Freedom

 * Kabiruddin Karim Ali, businessman
 * Marsha Feinland, retired teacher

American Independent
Despite Don J. Grundmann running, the American Independent Party gave their party endorsement to Republican Robert Lauten.
 * Don J. Grundmann, chiropractor

Election contest
In July 2012, Taitz sued to block the certification of the primary election results, alleging "rampant election fraud", but her suit was denied.

Candidates

 * Dianne Feinstein (D), incumbent U.S. Senator
 * Elizabeth Emken (R), former Vice President of Autism Speaks

Debates
No debates were scheduled. Senator Feinstein decided to focus on her own campaign rather than debate her challenger.

Counties that flipped from Democratic to Republican

 * Butte (largest city: Chico)
 * Del Norte (largest community: Crescent City)
 * Trinity (largest community: Weaverville)

By congressional district
Feinstein won 41 of the 53 congressional districts, including three held by Republicans.