Gay rights advocates are urging the court to overturn the ban, approved in November as Proposition 8, on the grounds it was put before voters improperly, or at least prematurely. Under state law, the Legislature must approve significant constitutional changes before they can go on the ballot.

Proposition 8's sponsors, represented by Pepperdine law school dean and former Whitewater prosecutor Kenneth Starr, said it would be a miscarriage of justice for the court to overturn the results of a fair election.