In the first and only vice-presidential debate of the 2024 election, Minnesota Gov. Tim Walz and Ohio Sen. JD Vance went head-to-head on the nation's most pressing issues.

With just over 30 days till Election Day, the debate stage offered both candidates an opportunity to appeal to undecided voters and help solidify the Democratic and Republican platforms.

The high-stakes, 90-minute debate was held at the CBS Broadcast Center in New York City on Tuesday.

As Walz and Vance made their cases for a Kamala Harris or Donald Trump-led White House respectively, ABC News live fact-checked their statements for answers that were exaggerated, needed more context or were false.

WALZ CLAIM: Gov. Walz said, "The persons closest to them, to Donald Trump, said he is unfit for the highest office. That is Senator Vance."

FACT-CHECK: True

Vance has shifted his view toward Trump since he first rose to prominence. Early in his career, Vance made a number of comments that were disparaging toward Trump. The specific comment that Walz seems to be referencing here is from a 2016 New York Times op-ed written by Vance ahead of the release of his book "Hillbilly Elegy." In the op-ed, Vance wrote, "Mr. Trump is unfit for our nation's highest office."

In years since the op-ed was published, Vance has said his views on Trump changed.

-ABC News' Allison Pecorin

VANCE CLAIM: Sen. Vance said, "We've got 20, 25 million illegal aliens who are here in the country."

FACT-CHECK: False

During Biden's administration, immigration officials have encountered immigrants illegally crossing the U.S. border around 10 million times. When accounting for "got aways" — people who aren't stopped by border officials — the number rises to about 11.6 million.

But encounters don't mean admissions. Encounters represent events, so one person who tries to cross the border twice counts for two encounters. Also, not everyone encountered is let into the country.

The Department of Homeland Security estimates about 4.2 million encounters have led to expulsions or removals. About 3.9 million people have been released into the U.S. to await immigration court hearings under Biden's administration, Department of Homeland Security data shows.

-PolitiFact's Maria Ramirez Uribe

VANCE CLAIM: Vance said Iran has "received over $100 billion... thanks to the Kamala Harris administration."

FACT-CHECK: False

Under President Barack Obama, Iran did take possession of $100 billion in unfrozen assets after the signing of the Iran nuclear deal, which Trump later overturned.

But Harris was not involved in the Obama administration. In August 2023, the U.S. announced an agreement with Iran to secure freedom for five U.S. citizens who'd been detained in the country in exchange for allowing Iran to access $6 billion of its own funds that had been frozen in South Korean banks.

The money consisted of Iranian oil revenue frozen since 2019, when Trump imposed a ban on Iranian oil exports and sanctions on its banking sector.

The agreement also included the release of five Iranians held in U.S. prisons.

In April 2024, Deputy Treasury Secretary Wally Adeyemo said that those funds had been once again frozen after the Oct. 7, 2023, Hamas terrorist attacks on Israel and had not reached Iran.

-PolitiFact's Louis Jacobson

VANCE CLAIM: Vance said, "There's an application... where you can go on as an illegal migrant, apply for asylum or apply for parole and be granted legal status."

FACT-CHECK: False

Vance's attempt to correlate the CBP One App process with Temporary Protected Status is incorrect, as is his assertion that it's akin to "the wave of a Kamala Harris open-border wand" and would "facilitate illegal immigration."

The CBP One App was created and launched under the Biden-Harris administration as a way to provide some migrants the ability to apply for an appointment at a port of entry to potentially file an asylum claim and seek other lawful pathways into the country. It is not a guarantee that those migrants will be allowed into the country, but it is a legal process through which they can request an opportunity to make their claim.

Separately, the Department of Homeland Security designates some countries Temporary Protected Status when they are deemed too dangerous for migrants to return to. TPS is a program that began in 1990 and was extended to Haitian migrants in 2010 under then-President Barack Obama after a devastating earthquake.

The protections were extended by the Department of Homeland Security under the Trump administration, although he subsequently tried to end protections, prompting court challenges. Biden most recently extended TPS this past June through Feb. 3, 2026. In order to be eligible for TPS migrants from those specific countries must already be residing in the United States at the time it's authorized.

-ABC News' Armando Garcia

WALZ CLAIM: Walz said, "Trump hasn't paid any federal tax in the last 15 years."

FACT-CHECK: False

Trump's tax records since 2020 have not been made public.

A congressional committee released portions of Trump's tax records from 2015-20. In some years, Trump paid no federal income tax. But not in every year. Trump's 2018 return declared a total income of $24.4 million, with a taxable income of $22.9 million.

Trump and his wife, Melania, paid $999,466 in federal income taxes. In 2019, the Trumps paid $133,445 in federal income taxes.

The New York Times reported in 2020 that Trump often paid no income taxes before being elected president, largely, they wrote "because he reported losing much more money than he made."

-PolitiFact's Aaron Sharockma

WALZ CLAIM: Walz was in China during the Tiananmen Square Massacre in Beijing

FACT-CHECK: False

Walz has repeatedly claimed he was in China during the Tiananmen Square, Beijing, protests during his year-long stint as a high school teacher in the southeastern Chinese town of Foshan starting in 1989.

Tonight he admitted that was false, saying he "misspoke" earlier, though he traveled to China in the months after the protests. The school Walz taught at was near Hong Kong. He was there as part of the WorldTeach program, a nonprofit affiliated with Harvard University.

But according to local newspaper clipping obtained by ABC News, it appears he did not actually travel to the country until August 1989, The pro-democracy protests, which led to a deadly government crackdown by the Chinese government, lasted from April 15 to June 4, 1989 — ending about two months ahead of Walz's travel to the country.

An article in the Chadron Record in Chadron, Nebraska dated August 11, 1989, said that Walz, a graduate of Chadron State College, "will leave Sunday enroute to China, where he will teach English and American history during the next year."

Walz has spoken about Tiananmen Square repeatedly -- why he supported the protests and why he stayed to be a witness.

As recently as in February, Walz said during an episode of the podcast "Pod Save America" that he was in Hong Kong during the protests. "I was in Hong Kong when it happened – I was in Hong Kong on June 4th when Tiananmen happened … Quite a few of our folks decided not to go in," he said, further expanding on the experience. "There was a lot of Europeans in Hong Kong [saying] don't do this, don't go, don't support them in this, and my thinking at the time was … what a golden opportunity to go tell how it was. And I did have a lot of freedom to do that, taught American history and could tell the story."

Walz, while serving in Congress as ranking member on the Executive Commission on China, said at a 2014 congressional hearing marking 25 years since the massacre that "as the events were unfolding, several of us went in." "I will talk a lot," Walz said tonight. "I will get caught up in the rhetoric. But being there, the impact it made, the difference it made in my life. I learned a lot about China."

-ABC News' Isabella Murray & Justin Fishel

VANCE CLAIM: Vance says Walz ended protections in Minnesota for babies born alive

FACT-CHECK: False

Infanticide, the crime of killing a child within a year of its birth, is illegal in all U.S. states.

In May 2023, Walz, as Minnesota governor, signed legislation updating a state law for "infants who are born alive." This change did not alter the fact that under state law, these babies are protected.

Previously, state law said, "All reasonable measures consistent with good medical practice, including the compilation of appropriate medical records, shall be taken by the responsible medical personnel to preserve the life and health of the born alive infant." The law was updated to instead say medical personnel must "care for the infant who is born alive."

The law's updated version also kept the provision that said, "An infant who is born alive shall be fully recognized as a human person, and accorded immediate protection under the law."

Every person who is born has legal protections under federal and state laws, experts told PolitiFact.

-PolitiFact's Sara Swann

WALZ CLAIM: Walz said, "Their Project 2025 is going to have a registry of pregnancies."

FACT-CHECK: Needs context

Walz has falsely claimed that Project 2025 will require pregnant women to register with a new federal agency designed to monitor their pregnancies. While the Project 2025 policy proposal is firmly against abortion, it does not call for monitoring pregnancies.

It does, however, call for states to track abortions more meticulously than current CDC rules mandate, or else face punishment like cuts to federal funding.

Vance and Trump have also both said that Project 2025 is not associated with their campaign. It's worth noting, however, that Trump told Time Magazine in April that states could decide to start monitoring pregnancies as a way to track illegal abortions, saying that overturning Roe vs. Wade returned those decisions to the states.

"I think they might do that. Again, you'll have to speak to the individual states. Look, Roe v. Wade was all about bringing it back to the states," he told Time.

More broadly on the subject of abortion, Project 2025 does call for an end to the FDA's approval of mifepristone, a widely used abortion medication, and calls for a revival of a 150-year-old law that bans the shipment of abortion-related equipment and medicine from being sent via the U.S. Postal Service, which would make it much more difficult for women who are taking the drug legally to access the care.

In August, Trump signaled he was open to revoking mifepristone access during a press conference in Mar-A-Lago when he responded to a reporter's question about whether he would direct the FDA to ban the drug.

"You could do things that... would supplement. Absolutely. And those things are pretty open and humane," Trump said, while also emphasizing at that conference that he wanted to "give everybody a vote" on the issue.

When asked to clarify those remarks, Trump's campaign pointed to the former President's belief that abortion laws should be left to the states. The former President has also said he would not sign a federal abortion ban into law.

-ABC News' Justin Fishel

VANCE CLAIM: Vance claimed that Trump made the Affordable Care Act stronger

FACT-CHECK: False

The Trump administration cut millions of dollars in marketing and enrollment aid for the law's health plans and backed failed congressional and legal efforts to overturn the law.

The Trump administration in June 2020 asked the Supreme Court to overturn the law in a case more than a dozen Republican-led states had brought; the high court rejected it.

Affordable Care Act enrollment declined by more than 2 million people during Trump's presidency, and the number of uninsured Americans rose by 2.3 million, including 726,000 children, from 2016 to 2019, the U.S. Census Bureau reported; that includes three years of Trump's presidency.

-PolitiFact's Matthew Crowley and Julie Appleby

WALZ CLAIM: Walz claimed children are NOT being used a drug mules

FACT-CHECK: Mostly true

According to Mexican immigration officials, it is very uncommon for children to be used to smuggle drugs. However, the federal government has warned in the past of youth being used by drug cartels.

Sources within the Mexican cartels consulted by ABC News in previous coverage say that their drugs are mostly being smuggled through regular points of entry by Mexican citizens with visas or by U.S. citizens.

-ABC News' William Gretsky and Anne Laurent