One of the hottest House races in the country right now is in Tucson, Ariz., where two Republicans are battling for the chance to take on Democratic Rep. Gabrielle Giffords, an incumbent high on national GOP takeover lists.

“It’s been competitive for a while,” said Republican state Sen. Frank Antenori of Tucson. “It’s just getting a little nasty now.”

The 8th district race has taken on a theme seen in previous GOP nomination contests this year. Jonathan Paton, a former state legislator, is the establishment candidate and faces a more difficult challenge than expected from fiery Jesse Kelly, who has local tea party backing.

A third Republican, Brian Miller, dropped out last week and is backing Paton, who has already released a new TV ad touting the endorsement. Andy Goss dropped out last month and encouraged his supporters to back Kelly.

Kelly, an Iraq War veteran, is outpacing Paton in fundraising and touts endorsements from a handful of Members of Congress. Fundraising reports due last week showed Kelly raised $79,000 from July 1 to Aug. 4, compared with Paton’s $46,000. While Paton has more money on hand, $187,000 to Kelly’s $79,000, much of that can only be spent in the general election.

When Paton entered the race in January, national Republicans felt they had a candidate who could defeat Giffords after two terms in Congress. Republicans were upset with previous nominee Tim Bee, the state Senate president and former grade school classmate of Giffords who local party leaders felt shied away from attacking her.

Kelly is running as the outsider and appeals to some of the more intense grass-roots Republicans, said Margaret Kenski, a longtime GOP consultant in Tucson.

“The question is, do Republican voters want someone who’s a complete newcomer or someone who does have some legislative experience?” said Kenski, who described the district as “more cantankerous than conservative.”

No matter who wins the primary, Republicans in the district want someone who will stand up to Giffords, a fiscally conservative Blue Dog Democrat who Republicans say has changed her immigration stance over the past year as she recognized how strong her re-election challenge would be. In a border district, there is no issue higher on voters’ radars.

“Whichever one wins, they need to go after her. They can’t pussyfoot around her,” said Antenori, who is not endorsing anyone in the primary. “Paton has more experience and because of that is more methodical. Kelly is just a brawler, and a lot of people just want to see him get through the primary so he can slap her around in the debate.”

As the underdog, Kelly has gone after Paton for his previous work as a lobbyist and questioned his commitment to enforcing Arizona’s much-publicized immigration law. Meanwhile, a group called the Conservatives for Congress Committee is airing an anti-Paton radio ad and recently released a poll showing Kelly ahead by a 2-to-1 margin.

Paton has played up his own experience in the state House and Senate, and until recently focused much of his campaign on Giffords. His campaign released a poll last month showing Paton and Giffords neck and neck in the general election. Paton has turned his attention to Kelly, with a recent direct-mail piece calling Kelly “soft as jelly” on the issues, the Arizona Daily Star reported.

With his short résumé, some have questioned whether Kelly has the background and experience to serve in Congress. The veteran is not a college graduate and works as a project manager for his father’s construction company.

The uncertainty surrounding the race leaves national Republicans unsure how viable a pickup opportunity the race provides. Still, both parties consider Giffords vulnerable. The Democratic Congressional Campaign Committee has reserved TV airtime in the district for the weeks leading up to Election Day.

The National Republican Congressional Committee weighed in on the 2006 GOP primary, following moderate Republican Jim Kolbe’s retirement. Despite the NRCC airing ads for its preferred candidate, state Rep. Steve Huffman lost to Randy Graf, a single-issue candidate who went on to lose to Giffords by 12 points.

The committee is not interfering in the Aug. 24 primary, even though many consider Paton their choice. Both Paton and Kelly are in the NRCC’s “Young Guns” program.

Giffords has amassed a $1.9 million war chest for the general election, so either Republican will be hard-pressed to match her in spending. However, Antenori said many voters have been holding off on donating until after the primary so their money will definitely go toward defeating Giffords.

But Antenori recognizes that even in a strong year for the GOP, Giffords will be difficult to unseat.

“Right now it’s probably a tossup between whoever wins and Gabby,” Antenori said. “It depends on whether they run a good campaign and whether they go after her. But if they run another touchy-feely campaign, I think she’ll win again.”