Mayor Gavin Newsom vowed Sunday to maintain San Francisco as a sanctuary for immigrants and do everything he can to discourage federal authorities from conducting immigration raids. The mayor cannot stop federal authorities from making arrests, Newsom told about 300 mostly Latino members of St. Peter's Church and other religious groups supporting immigrants. But no San Francisco employee will help with immigration enforcement. "I will not allow any of my department heads or anyone associated with this city to cooperate in any way shape or form with these raids," Newsom declared. "We are a sanctuary city, make no mistake about...