California Code, Elections Code - ELEC § 6340

(a) The Secretary of State shall place the name of a candidate upon the Republican presidential primary ballot when the Secretary of State has determined that the candidate is generally advocated for or recognized throughout the United States or California as a candidate for the nomination of the Republican Party for President of the United States.

(b) On or before the 88th day preceding a presidential primary election the Secretary of State shall publicly announce and distribute to the news media for publication a list of the candidates the Secretary of State intends to place on the ballot at the following presidential primary election. Following this announcement the Secretary of State may add candidates to the Secretary of State's selection, but the Secretary of State shall not delete any candidate whose name appears on the announced list.