Amazing. I was 90% sure he wouldn't. But I guess in politics, there's always that 10%.
What amazes me after a fast sweep of the political boards is that some Republicans think this is good news for them. Arnold staying out would have been good news for them because it would have made Riordan the front-runner. Richard Riordan has pretty much the same politics as Schwarzenegger but can't be accused of being unserious about the job or utterly inexperienced. He's also someone the Republicans could look to as a long-term center of power in the state. Yeah, Arnold's got the name value but he also has all that other baggage.
But some Democrats are also acting as if this is good news for them and I don't think it's that, either. Arnold will turn out the voters, especially some who may just love the idea of electing someone who isn't a career politician. That's one of the main sentiments that got Jesse Ventura his seat.
Seems to me the big loser in this is Riordan. That is, if he is/was going to run. And the other big loser (of course) is Darrell Issa who spent all that money to fund the recall and now may finish behind Gallagher.
You see why I don't write more on this site about comic books? It's because there's so much more hokey fantasy in this stuff.