SGR

Well, as far as I remember (I'm not a resident of Cali, I've only read about this stuff), Dems at the time were displeased with the incumbent governor (D). As a result, a sizeable share of them voted for Arnold (R). Like Trump, the celebrity factor and the wildcard factor he had probably worked in his favor. I believe about half of independents in Cali swung for Arnold.

I don't think, but correct me if I'm wrong, that the number of Dems in Cali that swung for Arnold and the number of independents in Cali that swung for Arnold are similar to the numbers of Dems/Independents that swing Republican in most recent presidential elections in Cali.

Arnold, of course, was not an average candidate, and, as far as I remember, though he was a Republican, he was fairly moderate in his beliefs and policy proposals.