(CNN) When pressed over and over again, Republican Sen. Martha McSally of Arizona would not say on Tuesday whether she was proud of her support of President Donald Trump in her debate against Democratic opponent Mark Kelly.
"I'm proud that I'm fighting for Arizonans on things like cutting your taxes," McSally said. "I'm proud to be fighting for Arizona every single day," she later added.
The response was simpler for Kelly, who called the President's overall behavior and actions in office "not acceptable."
McSally's response underscored her perilous position just four weeks before Election Day, as she tries to woo Trump supporters and independents in a state that appears to have turned on the President.
The debate touched on the US response to the coronavirus pandemic, health care, the filibuster and the Senate Republican effort to confirm a Supreme Court justice this month, among other issues. But as the country becomes increasingly polarized and partisan, Trump's standing in Arizona could define the Senate race and sink McSally.
The Arizona race is one of the most competitive in the country and crucial to the future control of the chamber. Democrats almost certainly need to defeat McSally to take back the Senate, and she tried to tie Kelly to liberal leaders, saying they would abolish the filibuster and install "the most radical agenda that we've seen." Kelly said he has not yet decided his position on the filibuster.
"My opponent is claiming that he's not a politician, or not even a Democrat, but that's counterfeit," said McSally. "The truth is that he is bought and paid for by Chuck Schumer, whose path to power goes through Arizona."
McSally has a compelling biography. In a campaign ad, she notes that she lost her dad at 12 years old, and was sexually abused at 17, before becoming the first woman pilot in the Air Force to fly in combat. "If you want flashy, you've got a guy," says McSally in uniform, after jumping into a cockpit. "But if you want a fighter, I'm your girl."
But even Republicans acknowledge that Kelly is one of the Democratic Party's strongest recruits of 2020. In July, David McIntosh, the president of the Club for Growth, a fiscally conservative group, told CNN that the Democrat is a "rock star candidate." The Navy captain and NASA astronaut is the husband of former Arizona Rep. Gabby Giffords, who was shot in the head and nearly killed in 2011 and is now a leader in the movement against gun violence.
Kelly has led most polls this year, and outraised McSally every financial quarter of the race. Liberal groups have spent or reserved an estimated $88 million to advertise in it, compared to an estimated $62 million for conservative groups, according to Kantar's Campaign Media Analysis Group.
"Mark Kelly has had a consistent lead in Arizona almost since the day he announced," J.B. Poersch, the president of the Senate Majority PAC, the top Super PAC for Democrats in Senate races, told CNN. "There hasn't been much looking back."
The race has pivoted over health care, especially during the coronavirus pandemic. McSally said on Tuesday that Kelly's support of a public health care option was "the first step to the government takeover of health care." Kelly has rejected those attacks, saying in one ad that he "will never vote to eliminate private health insurance."
On Tuesday, Kelly repeatedly went after McSally's votes to repeal the Affordable Care Act, which installed insurance protections for those with preexisting conditions, and reminded viewers than the late Arizona GOP Sen. John McCain voted to protect the health care law during the Republican effort to repeal it. Kelly charged that Republicans were rushing to confirm Supreme Court nominee Judge Amy Coney Barrett to get her on the bench in time to rule on a upcoming case on the constitutionality of the ACA. Kelly said McSally "paved the way" for the lawsuit, which he said could undermine the insurance protections for millions of Arizonans.
McSally fired back that she supports insurance protections for those with preexisting conditions and charged that Kelly wanted to delay the vote on Barrett so Democrats could confirm a "liberal, activist" justice.
But the debate hinged on the actions of the Trump administration.
When asked about its response to the pandemic, Kelly said, "200,000 dead Americans is evidence that ... Washington, this administration, and Senator McSally did not do a great job." He added that hundreds of thousands of Arizonans have lost their jobs "through no fault of their own" and the country needed more financial relief from Congress.
McSally touted that the administration and Congress struck deals on legislation worth trillions of dollars to protect small businesses, and credited Trump with limiting travel from China early on. McSally repeatedly suggested that Kelly was beholden to China due to his participation in US-China forums, and Kelly defended himself by pointing to his military record.
At one point, McSally was asked about Trump's reported comments that American war dead were "losers" and "suckers."
She said she would not comment on "anonymous sources" but that she has worked with the Trump administration to rebuild the military. Kelly said those comments from the commander in chief "absolutely" concerned him, and said McSally did not defend McCain, who Trump ridiculed for being captured and tortured during the Vietnam War.
McSally responded that she repeatedly asked the President both in private and public settings to stop attacking McCain.
"Quite frankly, it pisses me off when he does it," she said. "Let's let him rest in peace."
The candidates are running for the seat previously held by two icons in the Republican party: McCain and Barry Goldwater. But the state has dramatically changed to the Democrats' benefit, particularly in Maricopa County, which encompasses Phoenix and more than 60% of Arizona's residents. From 2010 to 2018, the county added over 593,000 people, according to the US Census Bureau, second only to the county that includes Houston, Texas. It was the fastest growing county in the country from 2017 to 2018.
In that time, the county and state have turned increasingly blue. In 2012, President Barack Obama and Vice President Joe Biden lost Maricopa by eleven points. In 2016, Democratic presidential candidate Hillary Clinton lost it by three points. In 2018, then-Democratic Rep. Kyrsten Sinema beat McSally by four points on her way to winning the seat of retiring Republican Sen. Jeff Flake. A recent New York Times/Siena College poll showed Biden leading Trump by nine points in the county and almost the same in the state.
Maricopa County Democratic Party chairman Steven Slugocki said the electorate is "very diverse" and "rapidly growing," with communities of color, younger people and people from outside the state pouring in.
"The Republican Party has lost its base here," Slugocki said.
Even some Republicans are worried that McSally will lose the seat, and some do not think she is conservative enough.
McIntosh told CNN that McSally is a "weak" candidate who "doesn't excite Republicans," and mentioned that she lost to Sinema in 2018 before being appointed to fill McCain's seat in 2019.
"Let's just say she didn't pull it off last time when she had a weaker opponent," McIntosh said. "I'm not too optimistic about this time."