PHOENIX — Little in Arizona cools off in the middle of August. One exception is the GOP's Senate primary election, where the wealthy businessman who spent $6 million of his own money on the race has scaled back his TV ad presence in what many see as tacit acknowledgment that he's failed to catch up to Rep. Jeff Flake.

With voting set for Tuesday, Wil Cardon has now taken a positive tone. He had pummeled Flake for four months on the state's airwaves, framing Flake as a Washington insider who is soft on illegal immigration and reneged on a pledge to serve three terms in Congress.

But the insider label has been hard to pin on Flake, who has frequently defied his colleagues, particularly on the issue of federal funding for pet projects, known as "earmarks." He is quick to remind voters that GOP leaders removed him from the House Judiciary Committee after his incessant criticism of earmarks.

Flake has also voted against the measures that have inspired GOP primary voters to turn out incumbents. He opposed the rescue of financial firms during the Bush administration, President Barack Obama's health insurance overhaul and the $787 billion economic stimulus package.

"Jeff has been a maverick in Washington trying to get things fixed," R.W. Hibbert of Maricopa said as he listened to the Republican candidates at a forum recently in Casa Grande, a town located about midway between Phoenix and Tucson. "He's not an insider. That argument doesn't work."

Amid a sluggish economy, Cardon's business background resonates with many voters. Cardon, 41, who has a master's degree from Harvard Business School, has run his family's real estate and energy business for the past dozen years. He tells audiences that the Senate suffers from a scarcity of lawmakers with personal experience in the private sector.

"I believe now more than ever we need businesspeople back in Washington, D.C.," Cardon tells voters at every stop.

"I'm a businessman," Bill Bridwell of Casa Grande said after listening to the GOP candidates. "I love the idea of sending businesspeople to the Congress. I would love the idea of Wil Cardon being elected to Congress. I think he represents my interests more completely."

Cardon had been spending $300,000 a week since the spring on local television, media consultant Scott Harkey of Phoenix said, but that spending essentially ground to a halt in August. Flake himself canceled up to $150,000 in ad buys scheduled to run in the final two weeks of the campaign, which Harkey said is a sign that Flake is reserving his resources for the general election against the Democratic nominee, former Surgeon General Richard Carmona of Tucson.

Also seeking the Republican nomination are former Youngtown Mayor Bryan Hackbarth and radio talk-show host Clair Van Steenwyk.

Flake, 49, is one of the rare Washington veterans who blends support from the political establishment with some of the forces that helped spur the tea party movement. Sen. John McCain and retiring Sen. Jon Kyl have endorsed him, as have the anti-tax Club for Growth and FreedomWorks for America, a tea party-friendly super PAC.

But some tea party leaders in Arizona are less enthusiastic about Flake. His past support for immigration reform is simply unacceptable to them. And they don't buy his comments that he now considers a comprehensive approach a "dead end" that he would no longer pursue.

"We don't trust that. We're smarter than that," said Annette McHugh of Glendale. "We would rather give a job-creator, a private-sector person a shot in D.C. rather than a typical insider, like Jeff Flake is perceived as."

GOP strategists and voters said that fatigue has set in on the immigration issue. While it was once far and away the most important issue with GOP voters in Arizona, the economy and jobs weigh just as heavily now.

Flake says he no longer supports a broad approach to immigration reform. He tries to explain to voters that legislation he co-sponsored in 2007 was an attempt to negotiate with Democrats to ensure immigration overhaul included such things as fines, paying back taxes and a requirement to learn English.

Still, the congressman said he remains sympathetic to those illegal immigrants brought to the United States as youngsters.

Cardon, who has maintained a busy campaign schedule in recent weeks, has taken a hard line against any illegal immigration and has called for building a double-layered fence at the border. However, he has been unable to leverage Flake's position on the issue as much as he would like.

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