California Code, Elections Code - ELEC § 7354

(a) The state central committee may prohibit or limit the power of county central committees established pursuant to Chapter 4 (commencing with Section 7400) to endorse, support, or oppose any candidate for nomination by the California Republican Party for partisan office in the direct primary election.

(b) The superior court, in any case brought before it by the state central committee or by any registered voter, may issue a temporary or permanent restraining order or injunction to prohibit the endorsement, support, or opposition by a county central committee of any candidate for nomination by the California Republican Party for partisan office in the direct primary election, if the endorsement, support, or opposition is in violation of the bylaws or rules of the state central committee. All cases of this nature shall be in a preferred position for purposes of trial and appeal, so as to ensure the speedy disposition thereof.