Jan. 31 (Bloomberg) -- California Governor Arnold Schwarzenegger will endorse John McCain's bid for the Republican presidential nomination, less than a week before the most populous U.S. state holds its primary election.

Schwarzenegger, a Republican, plans to announce his backing of McCain today in Los Angeles, said Jill Hazelbaker, communications director for McCain's campaign.

McCain, 71, has emerged as the front-runner for the Republican nomination following his victory in Florida's primary on Jan. 29, and an endorsement by Schwarzenegger will be an added boost to his candidacy going into the Feb. 5 contests known as Super Tuesday. California has 173 delegates at stake, almost 15 percent of the total needed to secure the nomination and the most among the 21 states holding Republican primaries or caucuses that day.

``The endorsement has cachet,'' said Barbara O'Connor, a political scientist at California State University in Sacramento. ``He is the quintessential, crossing party lines, post-partisan politician.''

Schwarzenegger's nod will mark the second major endorsement for McCain in two days. Yesterday, former New York Mayor Rudy Giuliani announced he was pulling out of the Republican presidential race and throwing his support behind McCain. New York, like California, is holding a primary on Super Tuesday.

While Schwarzenegger, 60, has been struggling to revamp the state's budget to deal with a growing deficit, he continues to enjoy high approval ratings in California. A Los Angeles Times/CNN/Politico poll published Jan. 16 found 60 percent of registered voters approved of the way he's handling his job.

`Fantastic Leader'

``Governor Schwarzenegger has been a fantastic leader for the state of California, and we are thrilled that he has thrown his support to McCain,'' Hazelbaker said in a statement.

Schwarzenegger and McCain are scheduled today to tour a Los Angeles company, Solar Integrated Technologies, that develops alternative-energy equipment.

California's Republican primary awards delegates by congressional district, with three delegates going to the winner of each of the state's 53 districts. Another 11 delegates are awarded to the overall winner in the state. Three delegates -- party leaders -- are unpledged.

Schwarzenegger's endorsement is important because California, unlike Florida and New York, doesn't award all its delegates to the statewide winner, since McCain is already favored to win the state, said Alex Vogel, a Republican strategist at Mehlman Vogel Castagnetti Inc. in Washington who isn't aligned with any campaign.

``It's not just a question of do you win,'' Vogel said. ``It's a question of how big do you win. I can't think of a better endorsement for McCain in California.''

To contact the reporter on this story: Edwin Chen in Washington at Echen32@bloomberg.net.

Last Updated: January 31, 2008 00:17 EST