He's got a mess in California, no question. As said, the state of the U.S. economy as a whole has to be considered.
However, one thing that must be considered is the heavy opposition he's had to face as governor. He has a legislature that has fought him every step of the way, made up of a group of people that would rather see him fail regardless of the state of the CA economy. CA is riddled with partisan politics perhaps worse than any state in the U.S. and it is a huge problem for the state...regardless of who the governor is.
