Supposedly the RNC believes that Carly has no chance against Boxer. If that’s the case, why not let a conservative run and give the voters a real choice?
Boxer destroys conservatives every time because she plays the "I'm a moderate - he's a white male right-wing extremist who will TAKE AWAY YOUR RIGHT TO CHOOSE!!!!!" card and no one in the media dares to say otherwise. She avoids debates and uses her influence to squash media coverage of her opponents. The only way to beat her is with image - running a younger, telegenic, libertarian-minded, and preferably already famous candidate against her. But the CA GOP doesn't have anyone like that. Carly Fiorina certainly isn't it - you would need to convince some Hollywood figure to do it.