Cal. Elec. Code § 3112

If by any act of Congress which is now or may become effective during the effective period of this section, provision is made for voting by special absent voter, that act shall control and be superior to any conflicting provisions of this code, and all state, county, municipal and district officers who are charged with the performance of duties with reference to the election laws of this state shall perform the duties and discharge the obligations placed upon them by that act of Congress. It is the purpose and intent of this section that full effect shall be given to ballots cast by special absentee voters under federal statutes in order that no person shall be deprived of his or her vote by virtue of having cast his or her ballot under any federal statute rather than under the laws of this state.