House Speaker Nancy Pelosi expressed deep disappointment on Friday that California voters approved Prop. 8, the measure banning same-sex marriage, and defended her ally, San Francisco Mayor Gavin Newsom, against critics who say his actions contributed to its passage. In a wide-ranging interview with The Chronicle, Pelosi said she believes some voters might not have fully understood the initiative, which overturned a state Supreme Court ruling legalizing same-sex marriage. The measure was approved 52 to 48 percent. "Unfortunately, I think people thought they were making a statement about what their view of same-sex marriage was," the San Francisco Democrat said....