Mr. Trump claimed his plan would “stimulate massive domestic auto production and make car ownership dramatically more affordable” for families.

But before he got to his new proposal, Mr. Trump often rambled, reviving his false claims about the 2020 election, mocking President Biden’s 2020 campaign crowds, praising Elon Musk’s rockets. At one point, as he criticized Vice President Kamala Harris, Mr. Trump did something that politicians rarely do: He took a pointed dig at the city that was hosting him.

“Our whole country will end up being like Detroit if she’s your president,” he said. “You’re going to have a mess on your hands.”

Gov. Gretchen Whitmer of Michigan, a Democrat, blasted Mr. Trump’s comments in a social media post, saying that “you better believe Detroiters won’t forget this in November.”

As Mr. Trump spoke about his proposals to revive the auto industry, he used some of the same kind of violent, cataclysmic language he often uses to vilify immigrants.

“After our victory in 2016, the Michigan auto industry was on its knees, begging for help, gasping,” he said at one point. Later, he claimed that international corporations had been allowed to “come in and raid and rape” the nation, a word choice he underscored. “That’s right, I used the word,” he said. “They raped our country.”

Mr. Trump’s proposals were the latest example of his dangling new, and expensive, tax benefits to groups of voters that he sees as key to his election chances next month. The former president has already called for eliminating taxes on tips, overtime and Social Security benefits. On Wednesday night, he released a statement calling for a tax cut for Americans who live abroad, who must still file a tax return with the Internal Revenue Service.

It is not clear how much it would cost the federal government in lost tax revenue if car loan interest were fully deductible.

Mr. Trump’s proposal to make interest on car loans tax deductible could be likened to the mortgage interest deduction, which Mr. Trump limited in the 2017 tax cuts that he enacted as president. Mr. Trump expanded the standard deduction, which has pushed far fewer Americans to itemize deductions on their tax returns. In 2017, before the law went into effect, 31 percent of Americans itemized their deductions on their tax returns, according to the Tax Policy Center. In 2020, just 10 percent of Americans itemized, the center found.

Higher-income Americans are much more likely to still itemize deductions on their tax bills — and therefore would be the main beneficiaries of Mr. Trump’s idea. (The mortgage interest deduction encourages people to buy homes, which tend to gain value over time; the merits of a federal tax policy that encourages people to borrow to buy automobiles, which lose value quickly, could be more questionable.)

During his speech Mr. Trump also promised to keep “Chinese-produced autonomous vehicles” off American streets, an effort already being undertaken by the Biden administration, which last month proposed banning Chinese-developed software from internet-connected vehicles in the United States. Though few Chinese vehicles are on U.S. roads, federal officials called the move a proactive effort to address potential national security issues.

Mr. Trump also reiterated many of his manufacturing proposals, including his call for tariffs and his plan to offer companies tax breaks and other benefits if they move their manufacturing to the United States or keep it there.

The former president also signaled that he was prepared to take more aggressive protectionist measures to shield the automobile sector from foreign competition in a second term, saying he would take steps to prevent China and other countries from passing products through other countries to avoid U.S. tariffs.

And Mr. Trump said he would formally notify Mexico and Canada that he planned to renegotiate the trade deal that he reached with them in 2018. He warned them again that he would seek to impose 100 percent tariffs on Chinese cars that are manufactured in Mexico and imported to the United States.

It had been expected that parts of the trade deal would be revisited in 2026. Mr. Harris said two weeks ago that she would open the review process. She was one of 10 senators to vote against the agreement.

Mr. Trump’s remarks, held at the Sound Board Theater inside the MotorCity Casino and Hotel, were given to an audience atypical for a Trump event. Unlike a raucous rally, the business leaders in the room were more muted in their response.

And the Economic Club’s president, Steve Grigorian, noted that a number of Democratic officials were in attendance, including Michigan’s secretary of state, Jocelyn Benson, who in 2020 faced armed protesters at her house chanting that they refused to accept that Mr. Trump had lost that election.

Mr. Trump acknowledged her attendance while complaining about Democrats’ stance on voter identification laws.

Before Mr. Trump’s speech, the Harris campaign held a call with Shawn Fain, the president of the United Automobile Workers, which endorsed Ms. Harris. Mr. Fain — who Mr. Trump attacked repeatedly during Thursday’s speech — criticized the former president’s economic record, saying his time in office was marked by “plant closings, job loss and union busting.”

Voters in the Detroit metropolitan area will be crucial if Mr. Trump hopes to win Michigan, a battleground state that helped deliver his victory in 2016 but that he lost in 2020. His speech on Thursday was his fourth event in the state in the last two weeks.

Polls have shown Mr. Trump and Ms. Harris locked in a tight contest in the state. According to a recent survey from The New York Times and Siena College, Mr. Trump’s perceived strength on economic issues has cut into an advantage that Ms. Harris held in early August, shortly after she replaced Mr. Biden on the Democratic ticket.

After speaking for nearly two hours, Mr. Trump sat down with John Rakolta, one of his former ambassadors to the United Arab Emirates, to take questions. As some people left the room, Mr. Rakolta acknowledged the lengthy remarks.

“That was a tremendous amount of information that you’ve given to us,” he said.

Andrew Duehren and Ana Swanson contributed reporting.

Adam Schiff, a Democratic congressman from Burbank, has led by an average of 20 points or more for months over Steve Garvey, a Republican from Palm Desert with no political experience. Still, Mr. Garvey’s candidacy has drawn outsize attention because of his years as a first baseman with the Dodgers and the Padres.

Outside Petco Park in San Diego on Wednesday night, fans of both teams were eager to see Game 4 of the National League division series. Less apparent was how they felt about Mr. Garvey’s candidacy.

David Roberts Jr., 25, a registered Democrat who works for the City of Chula Vista, Calif., was outside the ballpark with his father hours before the start of the game. The son admitted that he had not heard of Mr. Garvey — the politician or the baseball star — who stopped playing more than a decade before Mr. Roberts was born.

“I am not super into politics, especially the Senate and the House of Representatives, stuff like that,” Mr. Roberts said. “Obviously, it’s hard to not be aware of the presidential election, right? When it gets closer to election time, I’ll look into each specific matchup, who each person is.”

Even his father, David Roberts, 47, was only a child when he saw Mr. Garvey play in San Diego. The elder Mr. Roberts is a registered independent who grew tired of party politics. Still, he said that he leaned conservative and that he would most likely vote for Mr. Garvey.

“He’s a sports star trying to be in politics,” the father said. “If he was going to put himself through an election and a race and deal with all the mudslinging that comes with it, I feel like his heart is probably in the right place. He probably wants to do right by California.”

Mr. Garvey has built his campaign around his baseball career, which ended with the Padres in 1987. His website features a graphic of him swinging a bat and wearing a blue No. 6 jersey from his early stardom with the Dodgers. A video shows him wearing a similar jersey. He promotes his credentials as a 10-time all-star and the National League’s Most Valuable Player in 1974.

His baseball statistics notwithstanding, by campaign metrics, the odds are overwhelmingly against him.

Mr. Schiff, 64, is a former federal prosecutor and a 12-term congressman whose profile rose among Democrats when he led the first impeachment inquiry into former President Donald J. Trump. He had raised nearly $38 million in campaign contributions as of July, the most recent reporting period, more than three times the nearly $11 million Mr. Garvey had raised.

Democrats have an overwhelming advantage in California voter registration, 46 percent to 25 percent, and no Republican has won a statewide race in nearly two decades.

Mr. Garvey, 75, is still recognizable among older Californians who remember his baseball highlights and the celebrity status that lingered into his retirement, but he has made relatively few public appearances during his Senate campaign. He debated Mr. Schiff only once this fall, turning down other invitations.

He has tried to appeal across party lines, and a favorite line is, “I played for all of you.” He wants to control illegal immigration but wrote in an opinion essay this week in La Opinión that he does not support mass deportation of undocumented immigrants.

Still, Mr. Schiff has made the case that Mr. Garvey’s support of Mr. Trump and his personal opposition to abortion make him ill-suited to represent California.

And the congressman has amassed such a robust financial cushion that he recently talked up the money he has raised for fellow Democrats this election cycle — more than $7 million — and the significant contributions he has made to Vice President Kamala Harris’s presidential campaign.

As game time drew closer on Wednesday, the line of fans outside Petco Park snaked for blocks, wrapping around downtown buildings. Many fans were dressed head to toe in brown-and-gold Padres gear, but few said they would vote for Mr. Garvey simply because he had played for the team. As with most of America, they seemed divided along party lines.

Waiting to enter the stadium was Sonia Guzman, 58, who works in human resources and has followed the Padres since childhood. But she said she did not favor Mr. Garvey.

“He’s a little conservative for myself,” she said. “He aligns very closely with Donald Trump, and I will not be involved with that.”

Shawn Hubler contributed reporting from Sacramento.

On the Screen

The ad begins with an image of former President Donald J. Trump, slightly distorted by shadows, appearing to speak to wealthy supporters.

“I know about 20 of you and you’re rich as hell,” he says, according to subtitles that flash across the screen. The camera then cuts to a Black man watching Mr. Trump’s remarks on an iPad-like device and shaking his head.

After another image of Mr. Trump promising tax cuts flashes onscreen, the man introduces himself as “Buddy M.” from Allentown, Pa.

Buddy, pointedly declaring that he is “not rich as hell,” quickly establishes himself as a working- or middle-class American. The spot cuts between images of him — sitting in a wood-paneled living room, filling up a car at a gas station — and of fancily dressed people including Mr. Trump and his ally Elon Musk, the world’s richest man, who are separately hobnobbing in tuxedos.

As music soars, the spot cuts to images of Ms. Harris walking purposefully before American flags and greeting men wearing hard hats.

The Script

Trump

“I know about 20 of you and you’re rich as hell … We’re going to give you tax cuts …”

Narrator

“I’m not rich as hell. I’m the one that really needs the break, not the people that are already rich and have the money. The 1 percent don’t serve anybody but themselves, so for them to get a tax break? No, that’s not cool.

”Kamala Harris is going to make billionaires pay their fair share, and she’s going to cut taxes for working people, like me.

“I’m Buddy, and I’m not rich as hell, and I’m voting for Kamala Harris.”

Accuracy

Buddy makes several references to economic policy from both candidates.

When he mentions tax breaks for the “1 percent,” it may be a nod to Mr. Trump’s position of extending the 2017 tax cuts, which included tax benefits for the ultrarich, alongside other proposed tax cuts.

Ms. Harris supports raising taxes on the wealthiest Americans. She has also proposed an expanded child tax credit and tax cuts meant to spur home construction, along with a first-time home-buyer credit.

The Takeaway

The ad is an appeal to two groups of voters whose support Ms. Harris needs to shore up: Black men and working-class Americans of all races.

A national New York Times/Siena College poll of likely voters released last month found Ms. Harris winning 79 percent of Black voters, below the typical Democratic presidential performance of securing closer to 90 percent of Black voters, according to exit polls.

Ms. Harris has faced particular challenges with Black men. Buddy comes across as relatable — a regular working person rather than a celebrity — which may give him more authority to connect with voters of similar backgrounds.

Democrats have also struggled with white working-class voters. Buddy’s message — that Mr. Trump is out for himself and his rich friends, rather than for working people — and the images of Ms. Harris meeting with workers, many of whom appeared to be white, both seemed intended to engage those voters.

Linda Qiu contributed reporting.

“VOTE FOR TRUMP,” the sign read in 12-foot-tall letters, visible from miles away. The company went ahead with a lighting ceremony despite concerns from City Hall that the sign might distract passing motorists and pushback from critics who were baffled at the strident political stand of a printing company in a town of 18,000 residents.

It was worth the trouble, said Anthony Constantino, Sticker Mule’s chief executive.

“I’m here doing this on behalf of all Americans, Democrats and Republicans alike,” Mr. Constantino, 41, said at the event, flanked by mixed-martial artists and a pair of tangerine Tesla Cybertrucks. This was about celebrating free speech and togetherness, he said, and Mr. Trump was “the unity candidate.”

If recent polls are any indication, many of Mr. Constantino’s customers are not likely to agree.

It was the latest example of unusually bold politics in the risk-averse business world, at a time when partisan sentiment seems to be seeping into every facet of American life.

Companies have long tried to influence policy behind the scenes and, in recent years, some have been accused of “virtue signaling” for supporting causes like the Black Lives Matter movement.

But it’s still unusual for companies to give full-throated endorsements, and rarer still for the business to be so far removed from national politics.

Could it be a savvy business strategy? Research suggests no, but the move is making waves in the once placid world of sticker printing.

Sticker Mule first garnered attention for its politics in July, when Mr. Constantino said he sent an email with the subject “Trump 2024” to over four million mailing list subscribers. The email, in response to an assassination attempt on Mr. Trump, urged an end to political violence, before promoting a $4 T-shirt, marked down from $19. “I suggest buying one that shows you support Trump,” he wrote.

Confusion ensued. The online business operates all across the country, and in many international markets.

“I had to double-check who it was coming from,” said Adam Bredlau, 27, a Seattle resident who said he used to order T-shirts and magnets through the website for his punk band, Jet///Lag. “My initial thought was, Oh, I’m done, I’m not using them anymore,” he said.

Critics of the letter argued that the company made things worse when it began posting the email addresses of some respondents on social media.

In an interview, Mr. Constantino said the business was respectful of people with different opinions, and that it only exposed users who had sent his team death threats or other harmful messages.

The endorsement certainly attracted attention. The company’s website received almost 3.7 million visits in July, up 43 percent from the same month the previous year, according to Similarweb, an analytics company.

But that hasn’t translated to more sales, Mr. Constantino said. “We took a hit on this, but there’s an upfront investment to solve big problems.”

Purple Politics

In Amsterdam, where residents have recently elected candidates from both major parties, political opinions are a calculated risk for businesses. About 38 percent of city voters are Democrats, the biggest voting bloc, but independent and Republican voters are close behind, according to data from the Montgomery County Board of Elections.

The sign’s unveiling almost didn’t happen. Last week, the office of Mayor Michael Cinquanti, a Democrat, sought a temporary restraining order preventing the massive sign from being displayed, because it was a violation of zoning rules and could pose a hazard to distracted drivers.

Shortly before the lighting, a lawyer for Sticker Mule convinced a State Supreme Court judge to vacate the order, because it was not properly obtained.

Mr. Cinquanti said in a statement that the city had informed Mr. Constantino in August that the sign violated city codes, and that he could apply for variances, but there was no follow-up.

“If the same exact sign had the name ‘Harris’ instead of ‘Trump,’ our city would be taking the same exact actions to require the owner to comply with those same city’s codes,” he said, adding that the city still intended to make Mr. Constantino comply with the rules.

The company, which employs over 1,000 local residents, mostly in manufacturing, has many supporters. Founded in 2010, Sticker Mule opened in a former glove factory. Manufacturing, once a leading industry, has greatly diminished in the area. More than a fifth of the city’s population was living in poverty as of 2022, according to Social Explorer, a demographic data company.

At the sign’s lighting ceremony, hundreds of people filled the factory’s parking lot to hear from guest speakers including Henry Cejudo, a former U.F.C. champion, and Joe Mastroianni, a Conservative Party candidate for the State Assembly.

“It’s tacky to cloud business with politics, and Anthony never wanted to do that,” Mr. Mastroianni said in an interview. But beyond the endorsement, he said, the sign reflects a sentiment shared by conservatives, who feel shunned by others for their beliefs.

“It’s like coming out of the closet — it’s liberating,” he said. “That’s the best analogy.”

Bill Neiss, a city resident, said he showed up to support local business.

“Sticker Mule’s a big employer,” he said. “You see all these abandoned buildings? We need industry in this country.”

A Risky Stance

Mr. Constantino insists that the Trump sign was not motivated by business, but a bid to lower the temperature on political discourse.

“Most people do the risk-reward calculation and stay quiet,” he said. “The world needs to know there are influential, successful people who support the guy.”

The price for that support was not insignificant. Mr. Constantino formed a political action committee called Sticker PAC, which paid nearly $90,000 (from Mr. Constantino’s own pockets) for the 100-foot sign, according to public disclosures. The group has also printed more than 27,000 packs of pro-Trump stickers for his supporters, he said.

The moves have generated a lot of attention for the company. Mr. Trump, responding to an article about the lighting ceremony, wrote “Thank You!” and shared the piece with his 7.8 million followers on Truth Social.

Mr. Constantino is hopeful that the buzz will boost the company’s imminent launch of a new e-commerce platform that will focus on printing products for small-business owners. “We serve the masses,” he said.

But the bump could be short lived, said Vanessa Burbano, a professor at Columbia Business School who studies the behavior of businesses in the public realm.

For companies that make overt political statements, “all of my research suggests there is very little upside,” Dr. Burbano said, adding that people react more negatively when they disagree, but don’t often change their behavior when they’re in agreement with a company’s position.

The politicization of business started to pick up around the 2016 election, she said, and has backfired or produced middling results for a number of companies, like MyPillow, whose chief executive closely aligned with Mr. Trump. Expensify, a business software start-up, drew sharp criticism in 2020 for sending an email in support of Joseph R. Biden Jr.’s presidential campaign to its 10 million customers.

There are signs that much of the business world is once again retreating from politics, she said, which makes Sticker Mule something of an outlier.

Despite the company’s surge in traffic in July, after the Trump email, visits were down 12 percent in September, compared to the same month last year, according to Similarweb.

Mr. Constantino, however, was unbothered by the prospect of shrinking visits: “I think in the long run it’s going to elevate the brand.”

Paul Post contributed reporting. Susan C. Beachy and Jennie Coughlin contributed research.

Mr. Obama’s rally on Thursday in Pittsburgh kick-starts that effort. And he is expected to continue rallying Democrats to the polls in several more battleground state events in the coming weeks.

“You bring in someone like Barack Obama to inspire people, to encourage them to participate and to set the stakes and urge them to vote,” said David Axelrod, a former top strategist for Mr. Obama. “There’s no one better.”

Encouraging early voting is a key campaign strategy. As more Democrats cast their ballots early, it becomes easier for the Harris campaign to find and turn out the voters who are harder to reach.

Early voting has already begun in Pennsylvania, which Ms. Harris must almost certainly win to defeat former President Donald J. Trump. She holds a narrow lead in the polls there, having overcome the significant deficit she inherited from President Biden. Democrats are hoping for high voter turnout in the state’s biggest cities, Pittsburgh and Philadelphia.

But there are some worrying signs: Ms. Harris’s support among Black voters, for instance, is still lower than what Mr. Biden received when he won the state in 2020, according to a poll last month from The New York Times, The Philadelphia Inquirer and Siena College.

Black men in particular have been a weak point for Ms. Harris, and the vocal support of Mr. Obama, the first Black president, could help her there.

“He’s the biggest gun that Democrats have in their arsenal,” said Cornell Belcher, a Democratic pollster who worked on Mr. Obama’s presidential campaigns. “And here at the close, you’ve got to use the biggest gun you’ve got.”

Mr. Obama remains adored by Democrats, making him a natural surrogate for Ms. Harris on the campaign trail. More than 90 percent of Democrats and many independents view him favorably, according to an August survey by The Economist and YouGov — well above other Democrats, including Mr. Biden, Bill Clinton and Hillary Clinton.

“They’ve got to release the kraken,” said James Carville, a veteran Democratic strategist, adding that the Harris campaign should be using Mr. Obama and other high-profile surrogates more aggressively. “He’s got, obviously, tremendous appeal to Black voters. He has tremendous appeal to suburban whites, which is another big part of the coalition. And he drives Trump nuts.”

Only Michelle Obama polls similarly well. The Harris campaign has not yet said if the former first lady will hit the trail in the last weeks of the election. Many Democrats saw Mrs. Obama’s speech as one of the sharpest at their national convention this summer, but she has long been reluctant to spend much time on the campaign trail.

In his own convention speech, Mr. Obama cast Ms. Harris as the inheritor of his political movement, saying that it was “up to all of us to fight for the America we believe in,” and reviving the chants of “Yes, we can,” his 2008 campaign motto.

Ms. Harris was an early supporter of Mr. Obama, flying to Iowa in 2007 to knock on doors for the junior senator from Illinois when she was the district attorney of San Francisco.

In addition to campaigning for the top of the ticket, Mr. Obama is trying to help down-ballot candidates. Democrats running for Senate in Florida, Maryland, Michigan and Nevada have released ads featuring him. On Thursday, he is expected to also make a push for Senator Bob Casey of Pennsylvania, who is running for re-election.

The Harris campaign is treating the final stretch before Election Day as a multiweek voting period, urging supporters to return absentee ballots or to cast them at early-voting sites.

Gov. Tim Walz of Minnesota, the vice president’s running mate, and Ms. Harris’s husband, Doug Emhoff, spent Wednesday in Arizona to mark the first day of the state’s in-person early voting period. On Thursday, Ms. Harris is scheduled to record a town-hall meeting on Univision, which has a large audience of Spanish-speaking voters in both Arizona and Nevada. She will also hold a rally in Phoenix in the evening.

And in a sign that the campaign is acutely concerned about persuading Latino men to vote for Ms. Harris, it announced on Wednesday a voter-turnout effort called “Hombres con Harris” in Arizona, Nevada and Pennsylvania.

The pivot by the campaign toward exhortations to vote comes as it adopts a far more aggressive media outreach strategy. This week, Ms. Harris appeared on CBS’s “60 Minutes” and on the podcast “Call Her Daddy” and sat down for friendly discussions with Howard Stern, Stephen Colbert and the hosts of ABC’s “The View.”

Ms. Harris has also begun incorporating directives for supporters to not wait to return their ballots.

Last Friday in Flint, Mich., she reminded the audience that nearly two million voters in the state had already received their absentee ballots.

“If you have received your ballot, please do not wait,” she said. “Fill it out and return it today. Early voting starts statewide on Oct. 26, and now is the time to make your plan to vote because, folks, the election is here.”

Ms. Lake repeatedly accused Mr. Gallego of having undergone “an extreme makeover,” shifting from a progressive member of the House to a more moderate lawmaker whose views are more palatable to the majority of Arizonans, including the Republican voters Mr. Gallego is actively wooing. And she sought to skewer him on immigration, accusing him of being soft on the border.

“Ruben Gallego has supported — every step of the way — Kamala Harris, the border czar, and Joe Biden’s open border,” Ms. Lake said.

Mr. Gallego, who has worked to tack more toward the middle in the past year, especially on immigration, also talked tough, saying he was proud of votes during his time in Congress to bring more border agents to Arizona. He also hit back, accusing Ms. Lake of opposing a bipartisan border security bill for political expediency.

“You’ve been to Mar-a-Lago more than you have been to the border,” Mr. Gallego said at one point, referring to former President Donald J. Trump’s Florida resort.

Ms. Lake, whose vocal embrace of Mr. Trump’s lies about the 2020 election and hostility toward the state’s Republican establishment divided her party during her failed bid for governor two years ago, went into the debate well behind Mr. Gallego in most surveys of the race and in fund-raising, though both campaigns believe the race will tighten somewhat. Critically, Mr. Gallego is attracting the support of Republicans who also indicate they would vote for Mr. Trump.

It did not appear Ms. Lake landed the knockout blow she might need to reorient the race, even as she assailed Mr. Gallego in personal terms.

She invoked his father, a convicted drug dealer, and accused Mr. Gallego of using recipients of the Deferred Action for Childhood Arrivals program as “political pawns.”

“I find that to be disgusting, Ruben,” she said.

Mr. Gallego opted not to respond directly to Ms. Lake’s remarks about his father — but goaded her with the suggestion that Mr. Trump is less eager to associate with her as she trails in the polls.

While discussing abortion, Mr. Gallego pointed out that Ms. Lake was the one who had shifted stances, from being a vocal opponent of the procedure to saying she would oppose a federal ban. And Ms. Lake used the focus on women to suggest Mr. Gallego’s personal history with women was disqualifying, bringing up two decade-old harassment accusations made against him, which did not result in any action.

“Whenever she doesn’t have an answer, she just goes for personal attacks,” Mr. Gallego complained, saying one of the women who had made the accusation was now supporting his campaign. (Ms. Lake also misspoke while discussing reproductive rights, referring to in vitro fertilization several times as “U.V.F.” rather than “I.V.F.”)

Ms. Lake flashed some of the aggressiveness that has endeared her to Mr. Trump’s MAGA base — often interrupting Mr. Gallego to butt in with an attack — but he parried her capably, quickly ready with fact checks. Both sought to make the most of favorable issues: immigration, for Ms. Lake, and abortion, for Mr. Gallego.

She made what was perhaps her strongest argument — one that mirrors an attack Mr. Trump has made against Vice President Kamala Harris — only fleetingly: If Mr. Gallego was so focused on Arizona’s problems, why had he not addressed them already?

“I haven’t had a vote in this; you’ve had a vote for 10 years,” she said.

Mr. Gallego’s strongest message was one he hit on repeatedly, even though the moderators did not directly question her about it: her continued refusal to accept that she lost the 2022 governor’s race. Ms. Lake falsely insists she won, and has filed a series of fruitless lawsuits trying to overturn that election.

“She’s failed the basic test of honesty,” he said at one point, tying the issue to abortion. “Why would we trust her with our daughters?”

During a discussion of climate and water policy, Mr. Gallego brought up the issue again.

“Can you finally tell the people of Arizona: Did you win or lose that election?” he said.

Ms. Lake demurred.

“Can we talk about water really quickly?” she replied.