Gay rights supporters in California say they have found an unlikely ally in Cindy McCain, the wife of Republican Sen. John McCain of Arizona, who lent her name this week to the cause of same-sex marriage. McCain’s support comes as Proposition 8 proponents and opponents battle over the constitutionality of California’s ban on gay marriage in San Francisco federal court. The ad features McCain, right hand over her heart, wind rustling her blond locks, with “No H8” written on her cheek and silver duct tape over her mouth. “To have the wife of a Republican presidential candidate really turns everything...