The Republican congressman who bankrolled the effort to recall Gov. Gray Davis endorsed Arnold Schwarzenegger for governor Friday, saying the actor is the only candidate positioned to end what he called the failed policies of Davis and other Democrats.

Rep. Darrell Issa’s announcement, at Schwarzenegger’s campaign headquarters, appeared to have little effect, however, on state Sen. Tom McClintock, the one other prominent Republican still in the race to replace Davis.

About the same time he made it, McClintock unveiled a new campaign ad in Sacramento and said Schwarzenegger should step aside in favor of him.

“I give you with my wholehearted support Mr. Arnold Schwarzenegger,” Issa said as the candidate stood beside him beaming.

“Without a doubt,” he said, “only one man has been able to stand above the rest to make it clear that there will be a direction change away from the pay-to-play Bustamante-Davis way of doing business.”

The latter reference was a swipe at Lt. Gov. Cruz Bustamante, who is also running to replace Davis if he is recalled.

Although Issa never mentioned McClintock during his remarks, he released a written statement to reporters that said the conservative Republican’s “continued candidacy threatens to undermine the success of the recall election.”

The endorsement came a day after Davis himself challenged Schwarzenegger to debate him head-to-head.

Davis, who wasn’t invited to Wednesday’s barb-filled debate between five contenders for his job, thus emerged from it unscathed and appearing a bit more combative as he resumed his work as governor and took jabs at Schwarzenegger.

“I’m going to set the record straight. I’m getting sick and tired of his distortions,” Davis said Thursday. “If he doesn’t set the record straight himself, I may have to debate him.”

Schwarzenegger’s scrappy rookie performance earned him several endorsements that could provide a key boost to his candidacy with only a week and a half remaining until Election Day. Former candidate Bill Simon endorsed him on Thursday, as did the California Republican County Chairmen’s Association, a group of Republican committee leaders from California’s 58 counties.

Schwarzenegger, expressing gratitude for the endorsements, offered special thanks to Issa, who also at one point had considered running for governor.

“When he saw his campaign for governor not progressing the way he expected, what did he do? He did a selfless act, he stepped aside for other candidates to be successful. Big hand for him for that, for being so selfless.”

If that was a veiled reference to McClintock to do the same, the conservative Republican legislator ignored it.

He said Schwarzenegger should get out of the race rather than split the vote and hand a victory to Bustamante, the only prominent Democrat on the ballot.

“I would not be in this race if I did not believe I could win,” McClintock said. “You all know a lot can happen in the final days of a campaign. I’m the one moving up and gaining very rapidly, from what I’ve been told.”

In his statement, Issa said that wasn’t so.

“While he has ably articulated his vision for California, his campaign has failed to generate broad support and the special interests who are pouring money into his campaign now are doing so to divide the majority of Californians who support a fiscal conservative as a replacement for Gray Davis,” Issa said.

McClintock also criticized Schwarzenegger for refusing to sign a no-tax pledge.

“I oppose a tax increase on any Californian,” he said.

On Thursday he took Schwarzenegger to task for a new campaign ad that showed photos of McClintock, Davis and Bustamante as the actor accused unnamed candidates of “pandering” to casino-owning Indian tribes in return for campaign money.

Except for the photos, the ad is essentially the same as one Schwarzenegger unveiled on Monday. His campaign strategist Mike Murphy said it was sent to TV stations as a “contingency” and was broadcast in error.

The busy campaign activity resumed after Wednesday’s debate, which was filled with shouting, insults and wisecracks among the five leading candidates seeking to replace Davis. The debate frequently turned rowdy, and candidates routinely jumped on top of each other’s answers and shouted to be heard.

Some analysts said the raucous atmosphere may have played into Davis’ strategy of portraying the recall as a circus and going about the business of leading California.

“I think a substantial amount of viewers probably wanted to take a shower and think this whole recall thing is a big stinky mess,” said Marty Kaplan, associate dean at the Annenberg School of Communications, University of Southern California. “Should we empower this group of bickering mudwrestlers? You wanted to vote them all off the island.”

Observers said Schwarzenegger’s debate performance, while competent and often funny, also may have hurt him with women voters, who have not embraced the macho action star.

In his first and probably only debate of the campaign, Schwarzenegger repeatedly clashed with independent Arianna Huffington in a way that some analysts called overly aggressive.

“Where this could hurt him is if the exchange becomes a catalyst for discussion about Arnold and women in general,” said Arnold Steinberg, a GOP consultant and pollster who is not working for a candidate in the race.

Schwarzenegger’s aides dismissed the notion that the bickering was part of a pattern of treating women badly, as Huffington claimed.