San Francisco (AP) The mayor of San Francisco has his eye on another job.

Gavin Newsom, the democrat best known for challenging California's ban on same-sex marriage early in his first term, has filed papers to start raising money and conduct polls for a possible run for governor.

Newsom is 40 and if he ends up entering the race, one of his opponents for the democratic nomination could be a man 30 years his senior. California Attorney General Jerry Brown, who was governor from 1975 to 1983, has said he's thinking about another run