The judge in California's same-sex marriage trial had a pointed question for gay-rights advocates Tuesday: How can marriage between gay or lesbian couples be a fundamental right in a nation that denied all legal protection to their relationships until very recently?

Chief U.S. District Judge Vaughn Walker put sponsors of Proposition 8 on the spot with another question: In a state that treats domestic partners the same as spouses, "what purpose is served by differentiating - in name only - between same-sex and opposite-sex unions?"

Walker posted more than nine pages of questions for opposing lawyers to address in closing arguments next Wednesday in his San Francisco courtroom. The session is expected to go on all day.