SAN FRANCISCO  A federal appeals court has extended a stay on same-sex marriages in California until it decides whether a ban on such unions is constitutional.

It is just the latest turn in a protracted legal battle over Proposition 8, the voter-approved ban.

The ruling, issued by a three-judge panel of the United States Court of Appeals for the Ninth Circuit, came less than a week after a federal district judge, Vaughn R. Walker, lifted a stay he had imposed to allow proponents of the ban to argue why same-sex marriages should not proceed. On Aug. 4, Judge Walker ruled that Proposition 8 was unconstitutional.

Even when lifting his stay on Thursday, Judge Walker allowed six days for the Ninth Circuit to review his ruling. That left many gay and lesbian couples and their supporters hopeful that same-sex marriages would resume Wednesday at 5 p.m., when Judge Walker’s stay would have expired.

That will not happen. Now, such weddings will not resume until, at least, the appeals court decides the case. And perhaps not until it is decided by the United States Supreme Court, where it seems to be headed.