The three-judge 9th U.S. Circuit Court of Appeals panel said last month it needs to know if ballot proposition sponsors can step in when the attorney general and governor refuse to defend voter-approved initiatives in court.
A federal judge struck down Prop. 8's ban on same-sex marriage in August. Judge Vaughn Walker wrote, "Prop. 8 both unconstitutionally burdens the exercise of the fundamental right to marry and creates an irrational classification on the basis of sexual orientation." Supporters of Prop 8 then appealed that decision.
Former Gov. Arnold Schwarzenegger and Gov. Jerry Brown, who would have been responsible for enforcing the ban, both refused to challenge the ruling.
The Associated Press contributed to this story.