California's highest court refused to order Governor Arnold Schwarzenegger and the state's attorney general to appeal against a federal ruling that overturned the state's gay marriage ban.
The state Supreme Court denied a conservative legal group's request to force the state officials to defend the voter-approved ban.
The court did not explain why it rejected the emergency petition filed by the Pacific Justice Institute.
The institute argued that the attorney general and governor were required to uphold all laws, including initiatives passed by voters.
Earlier, lawyers for attorney general Jerry Brown and Mr Schwarzenegger filed letters with the court maintaining state officers have authority to choose which laws they challenge or defend in court.
"The governor, like any litigant, has complete discretion over his own litigation strategy, including whether or not to appeal an order," counsel Andrew Stroud wrote for Mr Schwarzenegger. "Here, the governor exercised his discretion and decided not to file an appeal."
Both men declined to appeal against Chief US District Judge Vaughn Walker's August 4 ruling that found the ban, known as Proposition 8, violated gay Californians' civil rights.
The measure approved by 52% of California voters in November 2008 amended the state Constitution to outlaw same-sex unions five months after the state Supreme Court legalised them.
Mr Schwarzenegger, who was under pressure from fellow Republicans to appeal against Mr Walker's decision, said he supports the judge's verdict.
Mr Brown, who is the Democratic nominee to succeed Mr Schwarzenegger as governor, said he cannot defend Proposition 8 because he agrees it is unconstitutional.
"Although it is not every day that the attorney general declines to defend a state law, the state Constitution or an initiative, he may do so because his oath requires him (to) support the United States Constitution as the supreme law of the law," deputy attorney general Tamar Pachter wrote on Mr Brown's behalf.