On a May day in 2009, Vaughn Walker was going through one of his weekly routines as a federal judge, reviewing a stack of new lawsuits assigned to his San Francisco chambers, when one case caught his eye: Perry v. Schwarzenegger. At the time, Walker had no inkling that history might rest in those pages, that one of the most important legal collisions in the nation over same-sex marriage might hang in the balance. In fact, at first, all Walker noticed was then-Gov. Schwarzenegger's name. But it did not take long for the veteran chief judge, himself quietly but openly in a longtime gay relationship with a doctor, to realize that he had inherited the legal challenge to Proposition 8, California's ban on same-sex marriage. The silver-haired judge with the iconoclast's reputation would be center stage in the gay marriage controversy. "That's when I had the —‰'Oh (my)' moment," Walker told this newspaper during an interview last week, recalling that he was already mulling retirement when the lawsuit landed on his desk.