Political party strength in California
California is a Democratic stronghold and considered to be one of the "Big Three" Democratic strongholds alongside New York and Illinois. Originally a swing state following statehood, California began regularly supporting Republicans for the first half of the 20th century. Republican dominance waned with demographic change, accelerating with increased immigration beginning in the 1980s. The party remained competitive with Democratic candidates until 1992. This changed amidst a struggling economy, when California flipped from Republican to elect Democrat Bill Clinton as President. Republicans still won statewide contests in the state until the late 2000s, with Arnold Schwarzenegger elected governor.
The following table indicates the party of elected officials in California:
- Governor
- Lieutenant Governor
- Attorney General
- Secretary of State
- Treasurer
- Controller
- Insurance Commissioner
- California Superintendent of Public Instruction
- Board of Equalization
- State Senate
- State Assembly
- State delegation to the U.S. Senate
- State delegation to the U.S. House of Representatives
Note that ties on the Board of Equalization are broken by the vote of the State Controller.
Party strength by number of registrations
;Graphical summary| Year | Total | Democratic | Republican | [Independent voter|] | American Ind. | Green | Libertarian | Natural Law | Reform | Peace & Freedom | Americans Elect |
| 1999 | 14,853,121 | 46.72% | 35.27% | 12.89% | 1.97% | 0.66% | 0.55% | 0.43% | |||
| 2001 | 15,577,686 | 45.57% | 34.76% | 14.43% | 2.04% | 0.91% | 0.60% | 0.35% | 0.48% | ||
| 2003 | 15,168,263 | 44.39% | 35.22% | 15.32% | 1.95% | 1.03% | 0.59% | 0.28% | |||
| 2005 | 16,628,673 | 43.04% | 34.49% | 17.88% | 1.99% | 0.95% | 0.54% | 0.17% | 0.40% | ||
| 2007 | 15,682,358 | 42.52% | 34.19% | 18.83% | 2.00% | 0.89% | 0.53% | 0.37% | |||
| 2009 | 17,334,275 | 44.52% | 31.14% | 19.99% | 2.17% | 0.67% | 0.48% | 0.32% | |||
| 2011 | 17,186,531 | 44.04% | 30.88% | 20.41% | 2.43% | 0.66% | 0.54% | 0.34% | |||
| 2013 | 18,055,783 | 43.93% | 28.94% | 20.86% | 2.64% | 0.63% | 0.61% | 0.34% | 0.02% | ||
| 2015 | 17,717,936 | 43.15% | 27.98% | 23.57% | 2.71% | 0.62% | 0.69% | 0.44% | |||
| 2017 | 19,432,609 | 44.77% | 25.87% | 24.51% | 2.63% | 0.49% | 0.73% | 0.39% | |||
| 2019 | 19,978,449 | 43.11% | 23.57% | 28.26% | 2.59% | 0.44% | 0.77% | 0.38% | |||
| 2021 | 22,154,304 | 46.17% | 24.14% | 23.73% | 3.07% | 0.39% | 0.92% | 0.48% | |||
| 2023 | 21,980,768 | 46.89% | 23.83% | 22.48% | 3.61% | 0.44% | 1.07% | 0.57% | |||
| 2025 | 22,900,896 | 45.27% | 25.22% | 22.34% | 3.91% | 0.48% | 1.02% | 0.62% |