It seems to me that one of the bedrocks of Democratic victories in Presidential (and other state wide races as well) is that the San Francisco Bay Area is Democratic both in its urban core, and wealthier suburban outer areas. In most American urban areas we find a liberal urban core, such as Detroit, Chicago, St Louis, Houston whatever, but this heavily Democratic area is usually at least partially neutralized by a conservative suburban area so the overall vote count isn't so strongly Democratic.
In the Bay Area, this neutralization effect is not in play, as the wealthier suburaban counties of San Mateo, Marin, Santa Clara and Contra Costa still lean Democratic to varying degrees, so the overall effect is a massive surge to the Democrats from the entire Bay Area. I'm wondering if anyone has done a study called "if Bay Area counties voted like other similar counties elsewhere in the country". My guess is that California would go from sure Democratic state to leans Democratic.
California would still be a pretty solid Democrat. If Republicans had an excellent candidate up, or someone from the state of California, we would have a shot, if we worked hard at it. In it's current state, the only way California would vote Republican is if the election was a landslide. One day though, who knows? California could start trending Republican. I question how liberal California is after the vote on Prop 8. (Thank you voters
)