Arizona getting to know Carmona in Senate race

They've also seen him described as President Barack Obama's personal recruit to serve as the next U.S. senator from Arizona. "Richard Carmona, Barack Obama's rubberstamp," says a recent ad from Republican nominee Jeff Flake.

Time will tell which narrative proves most powerful with the state's conservative-leaning voters, but Carmona's eye-popping resume is giving Democrats hope that they can pull an upset in Arizona and deliver a devastating blow to the GOP's prospects for winning control of the Senate.

Democrats now enjoy an effective 53-47 edge in the Senate. With fewer than a dozen truly competitive races out there, flipping retiring Republican Sen. Jon Kyl's Arizona seat would make it that much more difficult for the GOP to get to a majority.

Flake emerged from the state's bruising Republican primary elections a solid winner over businessman Wil Cardon, who spent more than $6 million of his own money, much of it on ads criticizing the six-term congressman. While Flake has had a constant presence on the airwaves, Carmona is still unknown to many Arizona voters. He had a relatively quiet primary and focused much of his time then on raising campaign money.

Flake, 49, said he understands why Carmona has focused most of his early ads on talking about what he's done in his life rather than where he stands on the issues.

"There's no doubt he has a great resume and he rightly wants to point to that, but part of the reason for that is he just hasn't developed positions on many issues," Flake said.

Flake cites health care as exhibit A. Flake voted against the Democratic-led effort to expand health insurance coverage and would vote to repeal it if he's elected.

Carmona, who served as surgeon general under Republican former President George W. Bush, has made it hard to discern where he stands on the law. His ad on health care states: "Republicans and Democrats both got it wrong. We've got to make health care affordable to small business and working families through innovation and preventive care while also cutting waste and fraud."

Carmona's campaign subsequently made clear he would not vote to repeal the law and would work to improve it, but that doesn't come through in his pitch to voters.

"That's about the best stand he can probably take. It doesn't really take a stand on health care, but it does avoid being stigmatized as pro-Democrat or Republican," said David Berman, senior research fellow at Arizona State University. "What has happened in Arizona politics is the strong emergence of independent voters. They like this bad-mouthing-both-parties kind of approach, and he needs these independent voters."

The voter registration records in Arizona indicate that about 36 percent of the state's voters are registered as Republicans, while independents make up a third of the vote and Democrats make up about 30 percent.

The two candidates each had about $1.7 million in the bank in the weeks leading up to their Aug. 28 primary victories. National Democrats have so far dedicated more than $1 million to the race. National Republicans announced Friday that they are jumping into the race as well with an ad campaign costing $570,000 that depicts Carmona as "handpicked by Obama." Flake is also getting help from the conservative advocacy group Club for Growth and tea party organizer FreedomWorks for America.