Supporters of Proposition 8, which would ban same-sex marriage in California, are running their first television ad.The commercial features San Francisco Mayor Gavin Newsom making a celebratory speech. The state Supreme Court had just invalidated a law overwhelmingly passed by voters in 2000 that declared "only marriage between a man and a woman is valid or recognized in California." Following is a text of the ad and an analysis by Aurelio Rojas of The Bee's Capitol Bureau: The ad Newsom: This door's wide open now. It's going to happen whether you like it or not.Narrator: Four judges ignored 4 million...