The Supreme Court on Monday morning temporarily blocked a federal judge in San Francisco from showing on YouTube proceedings from a trial that will determine whether a ban on same-sex marriage is unconstitutional.

The court's decision is not the final word; the stay sought by same-sex marriage opponents expires Wednesday. The court said that will permit justices "further consideration." The trial is scheduled to start Monday.

Justice Stephen G. Breyer was the only justice to object.

"I agree with the court that further consideration is warranted, and I am pleased that the stay is time-limited," Breyer wrote. But he said the court's standards for issuing a stay were not met because there is not a likelihood of "irreparable harm" if the proceedings were available on the Internet.

Two bay area couples are asking Chief U.S. District Judge Vaughn R. Walker to rule that same-sex marriage is a right embedded in the Constitution and that it was violated last year when California voters passed Proposition 8, a ballot measure confining matrimony to members of the opposite sex.