PHILADELPHIA — Sparring on politics and personality, Kamala Harris and Donald Trump showcased their starkly different visions for the country as they met for the first time Tuesday for perhaps their only debate before November’s presidential election, a high-pressure opportunity for the candidates after a tumultuous campaign summer.

The matchup offered Americans their most detailed look at a campaign that’s dramatically changed since the last debate in June which forced President Joe Biden from the race. The Democratic vice president immediately moved to press the case against the former Republican president and his bombastic rhetoric, linking him to the conservative Project 2025 blueprint for a Republican administration and GOP efforts to restrict abortion access.

Trump in turn tried to link Harris to Biden, questioning why she hadn’t acted on her proposed ideas while serving as vice president, and focused his attacks on Harris over her assignment by Biden to deal with the root causes of illegal migration.

As the former president made a series of false claims about migrants, Harris seemed to smirk as he said that migrants are “taking jobs that are occupied right now by African Americans and Hispanics.”

“Talk about extreme,” Harris responded, when Trump repeated unsubstantiated claims that immigrants in Ohio are eating their neighbors’ dogs and cats.

The candidates met in a small, blue-lit amphitheater converted into a television studio, with no live audience, meaning there was no rowdy applause, cheers or jeers. The intimate setting — with the candidates’ lecterns positioned less than 10 feet from each other — belied the contentious debate to follow.

Harris repeatedly shook her head derisively as Trump spoke, occasionally staring at him with a hand on her chin, while Trump seemed to avoid looking toward the Democrat. Trump hewed closely to his rally talking points and familiar attacks.

As Harris seemed to try to interject during one of his responses, Trump replied, “I’m talking now, sound familiar?" harkening back to a moment when shut down an interruption from then-Vice President Mike Pence.

Harris sharply criticized Trump for the state of the economy and democracy when he left office, as the COVID-19 pandemic ravaged the nation and after his supporters stormed the Capitol on Jan. 6, 2021, in a bid to overturn the 2020 presidential election.

“What we have done is clean up Donald Trump’s mess,” Harris said. She opened her answer by saying she expects voters to hear “a bunch of lies, grievances and name calling” from her GOP opponent during their 90-minute debate.

Trump, meanwhile, quickly went after Harris for abandoning some of her past liberal positions and said: “She’s going to my philosophy now. In fact, I was going to send her a MAGA hat.” Harris smiled broadly and laughed.

Harris has sought to defend her shifts away from liberal causes to more moderate stances on fracking, expanding Medicare for all and mandatory gun buyback programs — and even backing away from her position that plastic straws should be banned — as pragmatism, insisting that her “values remain the same.”

As the debate opened, Harris walked up to Trump’s lectern to introduce herself, marking the first time the two had ever met. “Kamala Harris,” she said, extending her hand to Trump, who received it in a handshake — the first presidential debate handshake since the 2016 campaign.

Harris, in zeroing in on one of Trump’s biggest electoral vulnerabilities, laid the end of national abortion rights at Trump’s feet for his role in appointing three U.S. Supreme Court justices who overturned Roe v. Wade, leaving more than 20 states in the country with what she called “Trump abortion bans.”

Harris gave one of her most impassioned answers as she described the ways women have been denied abortion care and other emergency care and said Trump would assign a national abortion ban if he wins.

Trump declared it “a lie,” and said, “I’m not signing a ban and there’s no reason to sign a ban.”

The Republican has said he wants the issue left to the states.

Harris used a question about her plans to improve the economy by saying she would extend the tax cut for families with children and a tax deduction for small businesses while attacking Trump’s plans to impose broad tariffs as a “sales tax” on goods that the American people will ultimately pay.

Trump was stone-faced during her answer but retorted: “I have no sales tax. That’s in incorrect statement. She knows that.”

Trump continued to call Harris a “Marxist,” and said “Everyone knows she’s a Marxist.” Harris’ eyebrows shot up and she made an amused face, cupping her hand on her chin and stared at him.

Trump, in turn, is trying to paint the vice president as an out-of-touch liberal while trying to win over voters skeptical he should return to the White House.

Trump, 78, has struggled to adapt to Harris, 59, who is the first woman, Black person and person of South Asian descent to serve as vice president. The Republican former president has at times resorted to invoking racial and gender stereotypes, frustrating allies who want Trump to focus instead on policy differences with Harris.

Harris hit Trump on one of his biggest sources of pride, his freewheeling campaign rallies. Harris noted how at the events, Trump, as he meanders through subjects, will sometimes muse on “fictional characters like Hannibal Lecter” and whether “windmills cause cancer,” and then said that if you watch his events “you will also notice that people start leaving his rallies early out of exhaustion and boredom.”

“The one thing you will not hear him talk about is you. Your needs, your dreams and your desires.”

Trump tried to use his next question to respond by accusing Harris of having no one attending her rallies except the people that he claimed, without evidence, that she has bused in and paid to be there.

“She can’t talk about that. People don’t leave my rallies. We have the biggest rallies, the most incredible rallies in the history of politics,” he said.

In rapid fashion after the June 27 debate between Trump and Biden, the incumbent bowed out of the race after his disastrous performance, Trump survived an assassination attempt and bothsides chose their running mates.

The debate is subjecting Harris, who has sat for only a single formal interview in the past six weeks, to a rare moment of sustained questioning.

The first early ballots of the presidential race will go out just hours after the debate, hosted by ABC News. Absentee ballots are set to be sent out beginning Wednesday in Alabama.