Brown has hinted at another run. If he runs for it he'll win the primary and another term. If he steps down, Newsom is the favorite.
Isn't Newsom rather unpopular?
Yeah, and that's been the case for a long time. He won San Francisco County by a huge margin in the 2010 election for Lieutenant Governor, and then the next day he was booed at the Giants' World Series victory parade. As the leader of the right-wing faction, he didn't exactly endear himself to the left in the City during his time as Mayor; his administration might reasonably be compared to Dianne Feinstein's. If he were to pursue higher office than the one he holds now (which, let's be honest, nobody cares about), he'll face a strong fight.
I agree with Ogre Mage that Kamala Harris will probably try to run for Governor or Senator in the next few years; I would probably vote for her. She's one of the least electable prominent Democrats in the state, but that shouldn't matter given how Democratic the state is nowadays; even with a very strong opponent in 2010, she still won.
