Martha McSally is drinking a Negra Modelo from the bottle at a Mexican joint here after another long day running in 103-degree heat for the honor of serving in an institution with a 13 percent approval rating.

She is the first female U.S. fighter pilot to fly in combat and the first woman to command a fighter squadron. As a lieutenant colonel in the Air Force, she sued then-Defense Secretary Donald H. Rumsfeld over the military requirement that servicewomen wear Muslim garb when off base in Saudi Arabia and got it changed.

It is in her constitution to charge hard at the very thing she’s been told is impossible and out of line.

Now, in her first bid for political office, she is going after the congressional seat that would seem most out of reach. Running as a Republican, she aims to replace the beloved Gabrielle Giffords, the Democratic congresswoman who was gunned down outside a Safeway on a Saturday morning while meeting with constituents, a crime that lacerated this community and horrified the nation.

To do that, McSally has to defeat the man who won a special election in June, Ron Barber, who was Giffords’s district director and was shot in the head that day.

Election 2012 race ratings: The race for House control

What kind of person runs against that legacy?

“Pioneer, leader, servant” is how the retired colonel, 46, introduces herself to those she seeks to represent in one of America’s flintiest swing districts.

“Am I nuts?” is what she first asked herself after plunging into a world that is as chaotic as the military is structured.

“The special election was about the legacy, and November is about the best representation for this district,” is what she had answered at the last event, when a supporter at a small meeting gingerly brought up “the Gabby factor.”

Now, at dinner, with her elderly dog at her feet and her nephew/driver/yard-sign toter eyeing her leftovers, McSally relates how she went from being a professor in Germany in January, teaching a course on the Arab Spring, to being a candidate a week after Giffords resigned.

It is a brash story about the advice she sought, heard and then ignored — to come home to the house she bought in 1994 when stationed here at Davis-Monthan Air Force Base, to put down her roots and run for school board or be a precinct chairman.

Don’t do it, you can’t be successful, you’ll be labeled a loser, she was told. Don’t blow your chances, with that impressive résumé and smarts and personal charisma, to be a political star. Take the conventional path.

“I had nothing to lose; I already had quit my job. So I said, ‘Now, what do I have to do? Probably file some paperwork, right?’ ” McSally, who is single, says with a grin.

Fighting a legacy

Ron Barber has the power of legacy on his side. He’s the link to Giffords’s fighting spirit and her care for her constituents.

Barber was by Giffords’s side on Jan. 8, 2011, as was usually the case since he had signed on as her district director in 2007. Before that, the contours of his life were prosaic.

A genial-looking man with gray hair and a gray beard, he had worked for more than 30 year as an administrator in the Arizona Division of Developmental Disabilities. He was married to his high school sweetheart. They had two daughters and four grandchildren — all of them in the Tucson area. He and his wife had a small side business, in which parents could trade and buy children’s toys and clothing.

That morning, Jared Loughner, a disturbed young man wielding a Glock 19 with 31 rounds of ammo, first walked up to Giffords at her “Congress on Your Corner” event at the Safeway and, at point-blank range, shot her in the head.

Then he opened fire on anyone in his sights, killing six and wounding 13. One of those hit was Barber, then 65, sending one bullet into his upper left leg, near his groin. Another hit him in the cheek and exited through his neck. He went through months of physical therapy to regain movement in his left leg.

A friend of Barber’s, U.S. District Judge John Roll, almost certainly saved Barber’s life that day. Surveillance video showed that he pushed him to the ground, helped him crawl under a table, and laid on top of him. As he did so, Roll was shot in the back and killed.

McSally, who had just begun to teach at the George C. Marshall Center for Security Studies in Germany, learned of the shootings from her pastor, while watching the livestream of a Tucson church’s Sunday service.

When Barber announced that he would seek election to replace Giffords, much of what he said seemed an ode to his former boss. He said he wanted to “help restore civility to our public life.”

Of Giffords, he said, “We have a very strong bond. I’m a moderate, like she is.”

Barber’s wounds and his connection to Giffords are not, of course, a qualification for Congress. But a lot of people would have been content to let him have the job. Or they may have been too timid to challenge him. Jesse Kelly, the Iraq war veteran and tea-party favorite who narrowly lost to Giffords in 2010, dropped out after he lost to Barber in the special election.

For better or worse, that is not how McSally is constructed. Her formerprofession, in some part, may explain that. In war, there are casualties. Losses are mourned, but sentiment is not part of the mission. She has never met Giffords or gone to look at the supermarket where so much carnage took place.

The rest of the explanation, the larger part, is McSally’s obvious relish for blazing the most difficult trails. She’s feisty and funny, blunt and occasionally profane.

When former Republican senator Rick Santorum took a stand against women in combat during his presidential bid, McSally went on television and said she “wanted to go kick him in the Jimmy” for saying that.

She went to a private lunch earlier this month to persuade an elusive donor to give to her campaign. “And I didn’t even have to give the pitch, because he said right away he was going to give me $2,500,” McSally recalled. “You know what I said? Are you married? Not because I wanted to date him! Because I wanted to know if he had a wife who could max out, too!”

Taking on politics

In her new career, it’s a great day when an attack ad is launched against you. It means somebody has decided it’s worth spending money to defeat you.

“I was . . . ooo, I’m almost a little afraid to look! My first attack ad!” McSally peers through her fingers as she campaigns before a dozen people in the housing business who are meeting at a local restaurant. The room breaks into laughter.

“And then I just had to crack up, because it’s a picture of me with recipe cards. . . . I’m in the kitchen cooking up bad recipes, which is in itself overtly sexist and insulting,” and the women in the room frown and shake their heads.

“I couldn’t tell if I was barefoot, too, they didn’t show my feet,” continues McSally about the ad, from House Minority Leader Nancy Pelosi’s political action committee.

“But c’mon! Me of all people! I spent 26 years in the military. I was too busy shooting 30mm out of my A-10 at the Taliban and al-Qaeda to even learn to cook!” And then the men all frown and shake their heads vigorously, too.

Long ago, McSally embraced daunting obstacles and accepted there would be distasteful tasks along the way. She gave the nuns trouble in high school and her mother trouble at home, then carried her defiance into the Air Force Academy, where she showed up with her hair an inch shorter than it was required to be.

(And there’s still trouble with that hair. “You wouldn’t believe how many supporters have something to say about how I look. I wear it down, they tell me to put it up,” she said with a laugh. “I pull it back, and they tell me to wear it down.”)

She didn’t decide to become a pilot until she realized that, at 5-foot-3, she was too short.

She badgered for two years to get a waiver and built up her leg muscles. She got a master’s degree in public policy from Harvard’s Kennedy School before entering flight school, the same year she won the military division of the Hawaiian Ironman World Triathlon.

She sued Rumsfeld after unsuccessfully trying through channels to change the abaya rule, which she insisted violated her religious freedom as an evangelical Christian and discriminated against her gender. She found support from an unlikely coalition of conservative Republicans and liberal feminists, which she now tells voters proves her ability to forge consensus around principle.

Her own political positions are not so easily categorized. She says her priorities are deficit reduction, economic growth, immigration and tax code reform, and protecting the border, 85 miles of which form the southern edge of her district. She’s antiabortion and supports Title X, a federal program that funds family planning.

Democrats have charged she will fall in lockstep with Republican leadership and privatize Social Security. The Arizona Republic endorsed Barber, praising McSally’s intelligence and energy but faulting her grasp of specifics of the issues.

The district is a true swing district, with its 376,000 registered voters divided nearly evenly between Republicans, Democrats and independents, and while most race-watchers still favor Barber to win, McSally has made it a tighter race than expected.

She has run mostly on her own biography and an assertion that, as a former commander, she will quickly gather all the pertinent intelligence rather than shooting off her mouth.

On the campaign trail

To be out in a congressional district not seen as competitive, in a state the presidential candidates ignore, is to observe a politicking that feels almost old-fashioned, unreconstructed, hopeful.

It is to hear of local concerns. There are bandits who are tearing up the border fence like Nascar pit crews. There is a foreclosure crisis that rivals neighboring Nevada. There is a palpable fear of how hacking up the military budget may necrotize a community.

People here are not prone to yammering about Big Bird’s allegiance. Or speculating about whether President Obama’s wedding ring shows obeisance to the caliphate.

“We got to get beyond the teddy bears, candles and flowers,” says Bill Odle, a rancher who lives on the border and is volunteering for McSally’s campaign. “We got real problems down here. You come down, and I’ll give you a tour. The colonel is very tough, and very smart, and she’s a firecracker. She’ll make stuff happen.”

At a candidates forum organized as part of a housing conference, McSally briskly runs through her experience and local bona fides, then gives an extended answer on how to find cuts within the nation’s military budget without hurting readiness or jobs in the district, which has two installations and a large Raytheon presence.

“There are efficiencies to be gained, believe me, I know about the Pentagon. You spend money at the end of the fiscal year to make sure you have it next year,” she says. “But our military can’t run on a budget-based strategy. It has to be a strategy-based budget.”

Then she adds, “If you elect me as your congresswoman, I won’t need a little staffer to whisper in my ear about some briefing paper.”

At each venue, she questions those attending about what they need from her. She listens intently to community bankers who want more flexible lending requirements than the too-big-too-fail boys, and to small businessmen who need reliability in a guest-workforce and to seniors anxious about their Social Security and Medicare.

And, at nearly every venue, at virtually every turn, she gets the “Gabby” question.

“We are rugged individuals,” she says at an event in Tucson. “We elect unique people to represent us in this district — Mo Udall, Jim Kolbe, Gabby Giffords. I resemble Gabby Giffords more than the man who worked for her, although I am grateful for his service.”

“I understand how people feel. The people of the district just lost their affable congresswoman, who was reasonable, and who listened to them,” she says at a stop in Phoenix.

“And, I guess what I would say is, well, who does that look like?” and she gives a little wave of her hand.