Republicans have a big built-in advantage in red-leaning Arizona. But Democratic Rep. Ann Kirkpatrick, who announced on Tuesday that she’ll challenge GOP Sen. John McCain in 2016, may be the party’s best chance at taking the Senate seat from the longtime lawmaker.

Boasting about her Arizona roots and small business experience, the 65-year-old, three-term lawmaker from Flagstaff said in a video announcing her bid that while she respects McCain’s service to the country, “I just believe our state’s changing.”

“Arizonans should have a real choice who they send to the United States Senate,” she added.

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While McCain, who is seeking a sixth term, has name recognition – especially as a former Republican presidential nominee and current chairman of the Senate Armed Services committee – one recent poll shows him struggling among Arizona voters. According to a survey earlier this month by the left-leaning Public Policy Polling, just 41% said they approved of McCain’s job performance, compared to 50% who disapprove. To make matters worse, just 21% who identified themselves as “very conservative” said they approved of how the lawmaker was doing.

In a hypothetical, head-to-head matchup, McCain is leading Kirkpatrick by just six points – 42% to 36%– according to PPP, with 23% saying they aren’t sure.

What could make McCain’s prospects more difficult is heated talk of a primary challenge from the right, with groups including Freedom Works and the Senate Conservatives Fund having said they would consider backing someone to take on McCain, who will be 80 years old by Election Day 2016. Something similar happened in 2010, when the tea party-backed J.D. Heyworth was a thorn in McCain’s side for months. This time around, names that have been floated include Rep. Matt Salmon and state Sen. Kelli Ward.

Some Republicans view McCain as too liberal, and if a serious challenger emerges on the right, McCain could potentially be forced to swing right during the primaries – something that could bite him later on.

Still, when it comes to the general election, Kirkpatrick should be considered as a serious challenger, according to Mike O’Neil, an Arizona political analyst and non-partisan pollster. “I’d rate her as first-rate opposition against McCain,” he said. After all, despite a 2014 GOP wave, Kirkpatrick managed to hold on to her seat against former Republican Arizona House Speaker Andy Tobin. That race was the most expensive congressional race in the state and she was helped by strong support from Native American votes in her rural district.

Kirkpatrick was first elected in 2008 before losing to the GOP’s Paul Gosar two years later. But she recaptured the seat in the Republican-leaning 1st Congressional District in Arizona in 2012—and held on to it in 2014. Kirkpatrick has voted in favor of Obamacare, has called for “comprehensive reform” of the country’s immigration policy, backs marriage equality and is pro-choice.

“In Congress, I’ve been working hard to put Arizona first: help create a strong, diverse economy; improve education; look out for Arizona’s farms, ranches and natural beauty; take care of our veterans; pay down our debt; protect Social Security and Medicare; and make Washington play by the same rules as everyone else,” she said in her announcement video.

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Kirkpatrick faces a number of challenges.

“She’s not well known in the rest of the state. She doesn’t have a state-wide profile. She needs a pile of money to make the case. But I think the record is such that if she could come across as someone who could give McCain a run for his money, the money would be there,” said O’Neil.

Ruth Jones, a political science professor at Arizona State University, said anyone who takes on McCain will face an “uphill battle” because “he has lots of money, he has strong network of people. He’s well connected in the Republican Party and this is a Republican state.”

When asked for comment about Kirkpatrick’s challenge, a McCain spokesman pointed to a statement put out by the National Republican Senatorial Committee. NRSC communications director Andrea Bozek tied the Democrat to Obama, arguing she “has been part of the problem in Washington and Arizonans are paying the price.” Bozek added, “She doesn’t doesn’t believe we should ‘second guess’ President Obama which is why she supported ObamaCare, his trillion dollar stimulus that crated jobs in China and cuts to Medicare. There is no question Ann Kirkpatrick has made life worse for Arizona families.”

Other Democrats whose names have been floated as potential challengers include Rep. Kyrsten Sinema, Fred DuVal who lost the 2014 governor’s race, and former U.S. Surgeon General Richard Carmona.