California Republicans are in open revolt against Gov. Arnold Schwarzenegger over his hiring of a Democratic operative as his new chief of staff. And one leading state GOP official is touting actor Mel Gibson as a possible Republican primary challenger to Schwarzenegger. Officials with the California Republican Party are said to be furious with Schwarzenegger and have demanded a private meeting with the governor to complain about his appointment of Susan P. Kennedy, who was a Cabinet secretary during the administration of Gov. Gray Davis. Schwarzenegger was elected governor after an extraordinary effort succeeded to recall Davis in 2003.