The decision, issued by a three-judge panel of the 9th U.S. Circuit Court of Appeals, trumped a lower court judge's order that would have allowed county clerks to begin issuing marriage licenses to same-sex couples on Wednesday.
Lawyers for the two gay couples that challenged the ban said Monday they would not appeal the panel's decision on the stay to the U.S. Supreme Court. They said they were satisfied the appeals court had agreed to expedite its consideration of the Proposition 8 case by scheduling oral arguments for the week of Dec. 6.
"We are very gratified that the 9th Circuit has recognized the importance and the pressing nature of this case by issuing this extremely expedited briefing schedule," said Ted Boutrous, a member of the plaintiffs' legal team. "Proposition 8 harms gay and lesbian citizens every day it remains on the books."
Attorneys for sponsors of the voter-approved measure applauded the decision. In seeking the emergency stay, they had argued that sanctioning same-sex unions while the case was on appeal would create legal chaos if the ban is eventually upheld.
"I think the basic notion that this case is not final until it's gone through the complete appellate process really prevailed," said Douglas Napier, a lawyer with the Alliance Defense Fund, a Christian legal firm.
"Rather than have this kind of pingpong effect of having the decision overturned, appealed and then overturned again, it's better to have this kind of decision," he said.
Under the timetable laid out Monday, it was doubtful a decision would come down from the 9th Circuit before next year.
A different three-judge panel than the one that issued Monday's decision will be assigned to decide the constitutional question that many believe will eventually end up before the Supreme Court and further delay a final outcome.
County clerks throughout the state had been preparing to issue marriage licenses to same-sex couples for the first time since Proposition 8 passed in November 2008. The measure amended the California Constitution to overrule a state Supreme Court ruling that legalized same-sex unions earlier that year.
"I'm sad, but I'm also glad that I didn't pay the $100 to reserve an appointment at the clerk's office," said Thea Lavin, 31, of San Francisco, who had planned to wed her partner, Jess Gabbert, 30, if the stay were denied. "This has happened so many times before where we take two steps forward, one step back."
Chief U.S. District Court Judge Vaughn Walker had ordered state officials to stop enforcing Proposition 8 beginning late Wednesday afternoon after ruling Aug. 4 that the ban violated the equal protection and due process rights of gays and lesbians guaranteed under the U.S. Constitution.
The ban's backers appealed that ruling and also asked the 9th Circuit to block same-sex weddings in the meantime. They claimed in papers filed with the 9th Circuit that gay marriages would harm the state's interest in promoting responsible procreation through heterosexual marriage.
Lawyers for two same-sex couples had joined with California Attorney General Jerry Brown in urging the appeals court to allow the weddings this week, arguing that keeping the ban in place any longer would harm the civil rights of gays and lesbians.
In a two-page order granting the stay, the appeals court panel did not indicate why it was keeping Proposition 8 in effect until it could consider the appeal of Walker's verdict.
But it ordered Proposition 8 sponsors to address in their opening brief due Sept. 17 whether they even have the legal right to try to have the trial judge's ruling overturned. Both California Gov. Arnold Schwarzenegger and state Attorney General Jerry Brown, the original defendants in the case, have said they support same-sex marriage and refused to defend Proposition 8 in court.
Walker presided over a 13-day trial earlier this year that was the first in federal court to examine if states can prohibit gays from getting married without violating the constitutional guarantee of equality.
Currently, same-sex couples can legally wed only in Massachusetts, Iowa, Connecticut, Vermont, New Hampshire and Washington, D.C.