Article II Section 6 California Constitution
Below is the content of Article II Section 6 of the California Constitution
(a) All judicial, school, county, and city offices, including the Superintendent of Public Instruction, shall be nonpartisan.
(b) A political party or party central committee shall not nominate a candidate for nonpartisan office, and the candidate’s party preference shall not be included on the ballot for the nonpartisan office.
See also: Article II Section 5 California Constitution