Wearing a bright smile, Kathy Barnette shook hands and introduced herself around the patio of a Montgomery County country club. “I’m Kathy, and I’m running for United States Senate,” she said.

But many already knew that. ”People are hearing my story,” she told one voter Monday. “The momentum has been amazing.”

Few would disagree.

Running on a shoestring budget and with a personal story that begins on an Alabama pig farm, Barnette has rocketed to the forefront of Pennsylvania’s crucial Republican Senate primary, according to both public and private polling. She’s picked up late momentum as she challenges her big-spending rivals Mehmet Oz and David McCormick.

Her rise in the final days before Tuesday’s primary has stunned operatives in both parties, upending a Senate race that could decide control of the chamber.

“Everyone knows Oz is running for this race. Everyone knows McCormick is running in this race, and they’re holding their nose,” Barnette said in an interview Monday. “When they break, the undecideds, they’re gonna break in my direction. There’s nothing [Oz and McCormick] can possibly say to these people ... that they haven’t already said, because they’ve spent such an insane amount of money.”

» READ MORE: From last year: She lost big in the Philly suburbs. She went hunting for voter fraud. Now Kathy Barnette is a rising GOP star.

Rival campaigns, along with news outlets, were scrambling this week to vet Barnette and her backstory. Top Senate operatives in both parties are so unfamiliar with her that they were at a loss about whether she’d make a strong general election candidate.

And on Thursday, former President Donald Trump jumped back into Pennsylvania’s Republican Senate primary, warning that Barnette “will never be able to win the General Election against the Radical Left Democrats.” But in the same statement, Trump, who has endorsed Oz, said that Barnette could have “a wonderful future” in the GOP and that he would back her if she’s properly vetted.

Questions are starting to simmer about some of Barnette’s links to fringe elements on the right, her false claims of voter fraud in the 2020 election, and some of her past incendiary comments — including a 2017 tweet about banning Islam and a 2010 opinion piece claiming that the “homosexual AGENDA” was seeking “domination.”

But with less than a week to go, it was also unclear if any of that would sink in with voters.

“She’s a gigantic question mark,” said one Washington Republican closely following the race.

And she’s gaining steam.

Wednesday brought her a major endorsement from the political arm of the fiscally conservative Club for Growth, which also announced a $2 million TV ad buy to boost her. A day earlier, the antiabortion Susan B. Anthony List backed Barnette, and a Fox News survey showed her effectively tied with Oz and McCormick, with all three polling within the margin of error of one another.

» READ MORE: Kathy Barnette is neck and neck with Oz and McCormick in the Pa. Senate race, poll says

Barnette, of Montgomery County, argues that undecided Republicans are looking for a more authentic alternative after hearing so much from Oz and McCormick on TV. Despite spending tens of millions of dollars on the race, the two men who have sucked up most of the attention have failed, so far, to win over a decisive share of the electorate.

“What [supporters] find in me is a sense of authenticity,” Barnette told The Inquirer. “They see me as one of them. And if our leadership is listening, then they would pay attention to that.”

McCormick and two super PACs funded by his wealthy allies have poured more than $35 million into the contest, while Oz and his supporters have spent more than $18 million. Each man put in at least $11 million of his own money.

Barnette’s campaign had spent less than $2 million as of April 27, according to the latest financial filings.

But Oz and McCormick often skipped smaller public forums and relied on big-name support (including Trump for Oz and Sen. Ted Cruz, of Texas, for McCormick), Barnette has kept a relentless campaign schedule, crisscrossing the state with a sharp-edged message and pugilistic debate performances. She would be the first Black person and the first woman elected to the U.S. Senate from Pennsylvania.

“I knew I would not be able to compete dollar for dollar with these people, but I believe I have a better message,” Barnette said. “And all I’ve done is just walk outside of my home to deliver that message.”

She has become the clear alternative to two top rivals who have each faced questions about their ties to Pennsylvania and their credibility as conservative or “America First” Republicans.

“Those two guys never caught on with anyone, and she filled that void,” said Vince Galko, a Pennsylvania Republican strategist who has advised a less prominent Senate candidate, George Bochetto.

She’s done it in part with a combative, unflinching style that has channeled the defiance that propelled Trump.

A win for Barnette could be a sign of the GOP establishment’s inability to steer the party. And her momentum comes at the same time that State Sen. Doug Mastriano (R., Franklin) appears to be pulling away in the governor’s race, worrying some Republicans that the two could be an unelectable ticket in two crucial campaigns this fall, despite a political environment that favors the GOP. The two sometimes campaign together.

Barnette, though, faces the challenge of turning her late momentum into a win with relatively little money, and increased scrutiny.

In 2010, for example, she wrote an online opinion piece for Canada Free Press denouncing “the homosexual AGENDA” on religious grounds.

“It is not equality that they so rabidly pursue,” she wrote. “It is domination! It is to the exclusion of the dominate [sic] voice in this country that inherently judges their lifestyle as immoral and perverse.”

On Tuesday a reporter at Inside Elections chronicled Barnette’s history of anti-Islam statements, including falsely calling former President Barack Obama a Muslim, tying the religion to pedophilia, and in 2017 tweeting that Islam “should be banned in the USA.”

Barnette and a campaign spokesperson didn’t immediately respond to messages seeking comment about those past statements.

» READ MORE: Trump’s smackdown of David McCormick shows the risks for Republicans trying a MAGA makeover

Barnette pursued false voter fraud claims after losing a 2020 House race to U.S. Rep. Madeleine Dean by 19 percentage points, organized buses to attend the Jan. 6, 2021, rally that preceded the Capitol attack, and has continued to cast doubts on the results of Pennsylvania’s 2020 presidential election, becoming a leading election denier in the state — along with Mastriano.

And Barnette has embraced an endorsement from former Trump National Security Adviser Michael Flynn, who pleaded guilty to lying to the FBI and has trafficked in conspiracies.

She played down her ties to Mastriano on Monday.

“I’ve been running on my own for a very long time,” she said. “I’ve done three events with him that I can think of, maybe four. So I have not been running on Mastriano’s ticket. However, I appreciate Senator Mastriano tremendously.”

The two, however, have at times been presented as a ticket and have a closing campaign rally scheduled together Saturday in Bucks County.

A longtime conservative commentator, Barnette has resonated in part through her distinct personal story. At one debate last month, she explained her strict antiabortion views by describing herself as the “byproduct” of a rape — that her mother was 11 years-old when she was conceived, and her father was 21.

In Lansdale on Monday, she recounted growing up on a pig farm “below the bottom rung of the economic ladder,” with no insulation and no running water. She was the first in her family to go to and finish college, and she later joined the Army National Guard.

“She has a presence about her. She definitely commands attention when she walks in a room or on a debate stage,” Galko said. “She’s fearless. She’ll go after the moderator, she’ll go after the person standing next to her.”

Barnette often says of the GOP establishment: “We have the best story to tell, we just keep picking people who suck at telling it.”

» READ MORE: Is Mehmet Oz really a conservative? We looked at the Pa. Senate candidate’s record.

Monday’s stop at the Montgomery County High School Enlistee dinner — she was asked to speak as a former member of the Army Reserves — came between interviews with Newsmax and the conservative podcasters Diamond and Silk, and ahead of a Tuesday drive to campaign in Elk County.

“We need people who are not part of the swamp,” said Judy Hummel, 75, a retired teacher who saw Barnette in Lansdale.

“She looks like she’s our savior,” interjected her husband, Dan Hummel, an Army veteran.

He was perplexed when Trump endorsed Oz, the celebrity surgeon widely known as “Dr. Oz.”

“He doesn’t even live in the state,” Hummel said of Oz, who lived in New Jersey for decades before deciding to run for Senate.“I watched the debate the other night, and every other word out of Oz’s mouth was ‘Trump.’ He had nothing to say for himself.”

Bob Kurtz, who lives in Bucks County, described himself as a moderate Republican who also likes some Democrats, including two of their Senate candidates, Lt. Gov. John Fetterman and U.S. Rep. Conor Lamb.

But he plans to vote for Barnette.

“I don’t agree with her on everything, but most of the time, I’m behind her,” said Kurtz, a retired Philadelphia teacher who also spent 28 years in the Army Reserve.

He didn’t think she had a real shot — until now.