He isn't being challenged, he isn't really being questioned. He's going to ride well in the polls until the Nomination is decided. There's no real evidence to suggest that Clinton would have a harder time in CA.
Than Obama?
I disagree. Western independents didn't poll favorably for Clinton even before Obama was in the race. It is not a group she will ever fill Obama's potential in. I don't think California will be competitive in even a semi-competitive race - I'm just saying, McCain could do better than 54-45. In fact, in an even race, 54-45 isn't a bad prediction.