2018 United States Senate election in California

The 2018 United States Senate election in California took place on November 6, 2018, to elect a member of the United States Senate to represent California, concurrently with other elections to the United States Senate, elections to the United States House of Representatives, and various state and local elections.

Under California's non-partisan blanket primary law, all candidates appear on the same ballot, regardless of party. In the primary, voters may vote for any candidate, regardless of their party affiliation. In the California system, the top two finishers — regardless of party — advance to the general election in November, even if a candidate receives a majority of the votes cast in the primary election. Washington and Louisiana have similar "jungle primary" style processes for U.S. Senate elections, as does Mississippi for U.S. Senate special elections.

The candidate filing deadline was March 8, 2018, and the primary election was held on June 5, 2018.

Democratic incumbent Dianne Feinstein won re-election in 2012 with 63% of the vote, taking the record for the most popular votes in any U.S. Senate election in history, with 7.86 million votes. Feinstein, at the time, was the ranking member of the Senate Judiciary Committee. She turned 85 years old in 2018, leading some to speculate that she would retire in January 2019, as her long-time colleague Barbara Boxer did in January 2017. However, Feinstein ran for reelection to her fifth full term, winning 44.2% of the vote in the top-two primary; she faced Democratic challenger Kevin de León in the general election, who won 12.1% of the primary vote. For the second time since direct elections to the Senate began after the passage of the Seventeenth Amendment in 1913, no Republican appeared on the general election ballot for the U.S. Senate in California. The highest Republican finisher in the primary won only 8.3 percent of the vote, and the 10 Republicans only won 31.2 percent of the vote among them.

In the general election, Feinstein defeated de León by an eight-point margin, 54% to 46%. This was Feinstein's closest election since 1994, as well as her last run for elected office, as she died in office in September 2023.

Advanced to general

 * Kevin de León, President pro tempore of the California State Senate
 * Dianne Feinstein, incumbent U.S. Senator

Eliminated in primary

 * Adrienne Nicole Edwards, Vice Chairwoman on the HDT Community Development Foundation board
 * Pat Harris, attorney
 * Alison Hartson, national director of Wolf PAC
 * David Hildebrand, legislative analyst
 * Herbert G. Peters, retired aerospace engineer and candidate for U.S. Senate in California in 2016
 * Douglas Howard Pierce
 * Gerald Plummer
 * Donnie O. Turner, Air Force veteran

Withdrawn

 * Topher Brennan
 * John Melendez, television writer and radio personality
 * Steve Stokes, candidate for the U.S. Senate in 2016

Declined

 * Ana Kasparian, co-host of The Young Turks
 * Joe Sanberg, entrepreneur and investor
 * Tom Steyer, hedge fund manager
 * Cenk Uygur, host of The Young Turks

Declared

 * Arun K. Bhumitra, businessman
 * James P. Bradley, businessman
 * Jack Crew, bus driver
 * Erin Cruz, published author
 * Rocky De La Fuente, entrepreneur and perennial candidate
 * Jerry Joseph Laws, candidate for the U.S. Senate in 2016
 * Patrick Little, neo-Nazi and Holocaust denier (denounced by California Republican Party)
 * Kevin Mottus, candidate for the U.S. Senate in 2016
 * Mario Nabliba, scientist
 * Tom Palzer, activist, retired city planner and candidate for the U.S. Senate in 2016
 * Paul Allen Taylor, businessman

Withdrawn

 * Donald R. Adams, businessman
 * Gary Coson
 * John Estrada
 * Timothy Charles Kalemkarian, perennial candidate
 * Ernie Konnyu, former U.S. Representative
 * Caren Lancona, businesswoman
 * Jazmina Saavedra, businesswoman and activist
 * Stephen James Schrader, veteran

Declined

 * Kevin Faulconer, Mayor of San Diego
 * Caitlyn Jenner, 1976 Olympic gold medalist and television personality
 * Arnold Schwarzenegger, actor and former Governor of California
 * Ashley Swearengin, former mayor of Fresno

Declared

 * Derrick Michael Reid, retired attorney and engineer and candidate for president in 2016

Declared

 * Michael V. Ziesing (write-in)

Declared

 * John Thompson Parker

Declared

 * Colleen Shea Fernald, perennial candidate
 * Rash Bihari Ghosh
 * Tim Gildersleeve, businessman and researcher
 * Michael Fahmy Girgis
 * Don J. Grundmann, California Constitution Party chairman and perennial candidate (Constitution Party)
 * Jason M. Hanania
 * David Moore (Socialist Equality Party)
 * Lee W. Olson
 * Ursula M. Schilling (write-in)
 * Ling Ling Shi, evangelist

Withdrawn

 * Jerry Leon Carroll
 * Michael Eisen, biologist
 * Charles Junior Hodge
 * Richard Thomas Mead
 * Clifton Roberts (Humane Party)

Polling

 * with Timothy Charles Kalemkarian, Caren Lancona, John Melendez, and Stephen Schrader


 * with Tom Steyer


 * with John Cox


 * with Xavier Becerra, Kevin Faulconer, Brad Sherman, Eric Swalwell, and Ashley Swearingin

Results
[[File:2018 CA US Senate primary.svg|thumb|250px|Primary results by county {{legend|#7996e2|Feinstein}}

{{legend|#ebf2ff|10–20%}}

{{legend|#dfeeff|20–30%}}

{{legend|#bdd3ff|30–40%}}

{{legend|#a5b0ff|40–50%}}

{{legend|#7996e2|50–60%}}

{{legend|#6674de|60–70%}} {{legend|#ae8bb1|Feinstein/Bradley tie}}

{{legend|#F9F1FF|10–20%}} ]]

Democratic candidates won a combined total of 4,231,444 votes, Republican candidates 2,216,223 votes, and other candidates 223,053 votes.

Debates

 * Complete video of debate, October 17, 2018

Predictions
Because of California's top-two runoff system, the seat was guaranteed to be won/held by a Democrat since the initial primary produced two Democratic candidates.

Polling

 * with Feinstein, de León, and Tom Steyer


 * with Feinstein, de León, and John Cox

Results
The race had an undervote of around 1.3 million votes compared to the gubernatorial election, likely by Republican voters choosing neither candidate. De León won many of the same counties and congressional districts won by Republican gubernatorial nominee John Cox, as many voters may have expressed opposition to the incumbent senator. No county voted for both Feinstein and Cox. Congressional districts 39, 45, and 48 were the only congressional districts that voted for both Feinstein and Cox.

Results by county
Results by county. Blue represents counties won by Feinstein. Cyan represents counties won by de León.

By congressional district
Feinstein won 39 of the 53 congressional districts. De Leon won 14, including seven held by Republicans and seven held by Democrats.