Former congresswoman Ann Kirkpatrick is entering the Democratic race to challenge U.S. Rep. Martha McSally, setting up what could be among the nation's fiercest House fights next year.

Months after losing handily to Sen. John McCain, Kirkpatrick has moved from the rural northeastern Arizona district she represented in Congress for six years to the southern district that includes parts of Tucson, the state's second-most populous city.

She joins an already-crowded field of Democrats, suggesting early energy on the left to face off with McSally, a Republican who easily won a second term in November only to see her approval rating sink after tying herself to the unpopular GOP health-care plan.

"I've been hearing from folks for months that there's so much at stake for our country right now: health care, the climate, our standing in the world, even the very fundamentals of democracy. They want a leader in Congress who can be a check on (President) Donald Trump," Kirkpatrick, 67, said in an interview with The Arizona Republic.

She called McSally "one of the ringleaders" in the GOP efforts to repeal the Affordable Care Act, which Kirkpatrick helped pass in 2010.

A crowded field

Matt Heinz, the Tucson doctor and former state lawmaker who lost to her last year, is running again. So is Bruce Wheeler, another former state lawmaker, Mary Matiella, a retired assistant secretary of the Army, and several others.

While the Democrats have numbers, it remains to be seen whether they can raise the money and votes needed to retake a seat that offers a window into the difficulty of winning back the House of Representatives.

The Heinz campaign said Kirkpatrick has a lot to prove to voters.

"According to Ann, she has lived her whole life in Northern Arizona, so it’s strange to see her hop to Tucson, register to vote on Wednesday, and announce her intention to run for Congress on Thursday," said David Waid, a spokesman for the Heinz campaign. "That she craves elective office is obvious, that she has any stakes or sweat equity in the community is what she’s going to have to convince voters of, and I think there’s a fair amount of skepticism about that."

Republicans immediately panned her decision.

"Career politician Ann Kirkpatrick just can't stay away — carpetbagging all the way from Northern Arizona to Tucson in her desperation to rejoin Nancy Pelosi in Washington," said Jack Pandol, a spokesman for the National Republican Campaign Committee. "The voters of Arizona have already rejected Ann's liberal record twice, and they will a third time in 2018."

"Democrats are putting forward yet another tried-and-failed candidate in Congressional District Two," said Torunn Sinclair, a spokeswoman for the Arizona Republican Party. "Ann Kirkpatrick fits the democrats' profile to a tee — she lost in 2016 against Sen. John McCain, and until recently she didn't even live in the district! She obviously didn't get the message last election: Arizonans don't want her to represent them."

Kirkpatrick enters her sixth race for federal office with more experience in Washington than McSally, and her vote for the ACA would bring a sharp contrast with McSally's support for the GOP plan.

But Kirkpatrick will also face questions about political opportunism by running in a new district and whether a three-term congressional veteran can bring something new to the legislative mix.

Kirkpatrick said she has family in the Tucson area and went to school and worked there at times in her life. She said she thinks she has deeper roots in the district than McSally and welcomes primary debates with her fellow Democrats in the race.

McSally's voting record

Republicans have controlled the House since the 2010 elections and, by next year's midterms, 20 of the past 24 years. While the Tucson area is often seen as a Democratic stronghold, Republicans have held a congressional seat there 20 of the past 32 years.

McSally coasted to victory by nearly 14 percentage points in 2016, even as Donald Trump lost in her district by nearly 5 percentage points. That disparity is among the largest in the country for GOP House members.

She already chairs a congressional subcommittee, a sign of leadership's support for her, and is among the most prolific fundraisers in the House. As an incumbent, McSally is likely to get financial backing from the NRCC, GOP leaders and right-leaning super PACs as well.

While money likely won't be an issue for McSally, her voting record will be.

Six months into President Donald Trump's administration, McSally has supported his agenda 97 percent of the time, according to roll call votes tracked by FiveThirtyEight, where the White House's view was known.

That most vividly includes the health-care bill that may now be politically stillborn with Senate Republicans seemingly abandoning the issue this week.

On the day in May the House passed its version, McSally reportedly exhorted her colleagues to get this "(expletive) thing" done. It suggested an enthusiasm for a deeply unpopular measure, at odds with her polite, presumed moderate conservatism.

Throughout the year, McSally has only gently rebuked Trump for firing former FBI Director James Comey, calling it "deeply concerning," and has scarcely shown support for the unanimous view of the intelligence community that Russia interfered in the 2016 presidential election.

What she has done is continue to focus on the traditional needs of her district. She has, for example, helped ensure the House's proposed Pentagon budget includes continued funding for the A-10, a key part of the fleet at Tucson's Davis-Monthan Air Force Base and more Tomahawk missiles from Raytheon.

Heinz raised $201,000 for his latest campaign in little more than two weeks back in the race. Matiella, a retired assistant secretary of the Army, collected $31,000 in about the same span.

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