Gov. Arnold Schwarzenegger, who is expected to travel to Ohio on Friday to stump for President Bush, campaigned Monday alongside San Francisco Democratic Mayor Gavin Newsom -- underscoring his differences with the White House on two critical issues, same-sex marriage and stem cell research. Schwarzenegger took the stage with the San Francisco mayor at a press conference to illustrate their bipartisan support for Prop. 1A, a state ballot initiative aimed at preventing the state legislature from taking local tax funds. But, questioned afterward, the governor downplayed plans for a last- minute campaign swing for Bush, and instead praised Newsom as...