The topics included fighting COVID-19, American families, race in America, climate change, national security and leadership.
Below, ABC News fact checks what both candidates said throughout the 90-minute debate, moderated by NBC News White House correspondent Kristen Welker.
Trump misleads when comparing COVID-19 pandemic to H1N1, Obama administration response
TRUMP'S CLAIM: "Frankly, [Biden] ran the H1N1, swine flu, and it was a total disaster, far less lethal, but it was a total disaster. Had that had this kind of numbers, 700,000 people would be dead right now."
FACT CHECK: While Trump is correct that the H1N1 virus was much less lethal than COVID-19, it is misleading to call the Obama administration's response a "failure."
The Centers for Disease Control and Prevention estimates up to 575,000 lives were lost to the swine flu worldwide. Of those, fewer than 13,000 were American, due in part to the Obama administration's "complex, multi-faceted and long-term response," the CDC later wrote. Thus far, COVID-19 has taken the lives of over 210,000 Americans, a little over eight months since the first known case of the virus was discovered in the United States.
"The team, in my opinion, in 2009, really demonstrated that the planning was worth it. Nothing is ever perfect. But I felt just so impressed and so proud of the job CDC did in 2009," Dr. Julie Gerberding, a CDC director during the George W. Bush administration, told ABC News.
Biden incorrectly attributes mask statistic to Trump advisers
BIDEN'S CLAIM: "The expectation is we'll have another 200,000 Americans dead in the time between now and the end of the year. If we just wore these masks, the president's own advisers have told him, we could save 100,000 lives."
FACT CHECK: The president's advisers haven't used this estimate, though the head of the Centers for Disease Control and Prevention has strongly recommended wearing them. A modeling study by the University of Washington estimated at one point that if most Americans wore masks, it could save 100,000 lives by the end of the year. That estimate has been repeated by Tom Frieden, who led the CDC under President Barack Obama.
Dr. Robert Redfield, the current head of the CDC under Trump, has not made such a statement.
According to his office, he has said that the pandemic could begin to come under control in eight to 12 weeks "if all people living in America wore a face mask, were smart about social distancing and crowds, and practiced good hand hygiene."
Trump says Biden called China travel restrictions ‘xenophobic,' but that's not clear
TRUMP'S CLAIM: "When I closed, he said, 'This is a terrible thing. You're xenophobic.' I think he called me racist, even, and -- because I was closing it to China. Now, he says I should have closed it earlier. It just -- Joe, it doesn't work."
FACT CHECK: While Trump claimed that Biden opposed his decision to ban most travel from China at the outset of the coronavirus pandemic and that he called the restrictions "xenophobic," the former vice president did not explicitly weigh in on the decision when it was announced on Jan. 31. He did call the president xenophobic minutes after the partial travel ban was announced, but did not call Trump a racist for the decision.
During a campaign event that same day in Fort Madison, Iowa, Biden discussed the growing concern over the COVID-19 outbreak and cautioned that Trump should let science "lead the way."
"In moments like this, this is where the credibility of a president is most needed as he explains what we should and should not do," Biden told the crowd at the event. "This is no time for Donald Trump's record of hysterical xenophobia ... and fear-mongering to lead the way instead of science."
The comments came just minutes after the White House announcement, so it was unclear if Biden was referring to the decision specifically, but the former vice president did tweet a similar sentiment the next day.
"We are in the midst of a crisis with the coronavirus," Biden posted. "We need to lead the way with science -- not Donald Trump's record of hysteria, xenophobia, and fear-mongering. He is the worst possible person to lead our country through a global health emergency."
Throughout March, Biden used the word "xenophobic" in various speeches and tweets to criticize the president labeling COVID-19 as the "China virus."
Biden did acknowledge the travel restrictions put in place by the Trump administration in a March speech, noting they "may" slow the spread.
"Banning all travel from Europe or any other part of the world may slow it, but as we've seen, it will not stop it. And travel restrictions based on favoritism and politics rather than risk will be counterproductive," Biden said.
Biden's campaign did not explicitly discuss the vice president's view of the ban until April.
"Joe Biden supports travel bans that are guided by medical experts, advocated by public health officials and backed by a full strategy," Biden's deputy campaign manager Kate Bedingfield told CNN. "Science supported this ban, therefore he did too.
Trump misstates Fauci's past comments on masks
TRUMP'S CLAIM: "Nobody knew where it was coming from, what it was. We've learned a lot. But Anthony said don't wear masks. Now he wants to wear masks."
FACT CHECK: Dr. Anthony Fauci, one of the top infectious disease experts in the country, and other public health experts initially told Americans not to wear surgical or N95 masks in the early days of what has become the COVID-19 pandemic.
At the beginning of the pandemic, the Centers for Disease Control and Prevention and the World Health Organization, as well as Fauci and other top experts, initially discouraged wearing masks because of concerns that masks and other personal protective equipment were in short supply for health care workers who needed them. Public health officials were also concerned wearing masks could have unintended consequences if people touched their face more often to adjust them or fail to keep social distancing.
"There was this feeling that there would be a shortage just for those who really need them very early on," Fauci said in a recent interview. "That was the big deal. We didn't have enough PPE including masks. Then it became clear that cloth masks worked reasonably well. And therefore there was no more shortage. Then the different analyses, meta analyses and others came in that in fact, it does work."
In early April, the CDC changed its recommendation about face coverings for the general public, based on evidence that a significant number of people who were asymptomatic or not yet feeling sick were transmitting the virus.
Duke University researchers have also concluded that "if 95 percent of people wear cloth masks when within 6 feet of other people in public, it will reduce COVID-19 transmission by at least 30 percent."
Trump also said he thought Fauci was a Democrat, but Fauci is not registered as a member of any political party, according to D.C. voting records.
--Stephanie Ebbs and Arielle Mitropoulos
Trump says he was told by DNI that both Iran and Russia want him to lose the election
TRUMP'S CLAIM: "Through John, who is -- John Ratcliffe, who is fantastic, DNI. He said the one thing that's common to both of them [Russia and Iran], they both want you to lose because there has been nobody tougher to Russia with -- between the sanctions. Nobody tougher than me on Russia."
FACT CHECK: While it is unclear whether Trump's director of national intelligence, John Ratcliffe, told him personally that Russia hopes he would lose the upcoming election, such a statement would contradict what the U.S. intelligence committee has determined.
In August, the Office of the Director of National Intelligence assessed "that Russia is using a range of measures to primarily denigrate former Vice President Biden and what it sees as an anti-Russia 'establishment.'" The office has never stated publicly that Russia hopes Biden will lose the upcoming election.
As for Iran, the office said it determined the country in its interference efforts "seeks to undermine U.S. democratic institutions, Trump, and to divide the country in advance of the 2020 elections."
Ratcliffe in a Wednesday evening news conference revealed both Iran and Russia recently obtained voter registration data in their efforts to interfere in the 2020 election, and that Iran was separately behind "a series of threatening emails that were found to be sent this week to Democratic voters," which he said was "designed to intimidate voters, incite social unrest and damage President Trump."
But Democratic leaders have argued Ratcliffe may have inflated Iran's motivations relating to Trump and instead the country was seeking more broadly to sow chaos in the U.S. democratic process.
U.S. officials have also characterized to ABC News that Russia's interference efforts both in 2016 and 2020 far exceed that of Iran's in both scope and complexity.
Trump misleads on fundraising
TRUMP'S CLAIM: "Joe, you have raised a lot of money, tremendous amounts of money and every time you raise money, deals are made, Joe. I could raise so much more money as president and as somebody that knows most of those people. I could call the heads of Wall Street, the heads of every company in America. I would blow away every record, but I don't want to do that because it puts me in a bad position."
FACT CHECK: Trump targeted Biden for raising money for his campaign by claiming he could raise more but would be put in a "bad position" because he would owe donors something in return.
However, Trump himself regularly holds private, high-dollar fundraisers raking in millions of dollars and has raised over $1.5 billion so far this election cycle.
Just a week ago, the president attended a closed-door fundraiser at the home of Nicole and Palmer Luckey, an entrepreneur -- where tickets ranged from $2,800 up to $100,000 per person.
Trump overstates vaccine readiness timeline
TRUMP'S CLAIM: "We have a vaccine that's coming. It's ready. It's going to be announced within weeks. And it's going to be delivered." // "Johnson & Johnson is doing very well. Moderna is doing very well. Pfizer is doing very well. And we have numerous others."
FACT CHECK: A COVID-19 vaccine isn't ready right now. But it is true that two companies -- Pfizer and Moderna -- could seek emergency use authorization in November or December.
Like Pfizer and Moderna, Johnson & Johnson's vaccine is also in late-stage studies, but Johnson & Johnson paused its trial earlier this month to investigate an unexplained illness.
As the chief adviser to the government vaccine distribution initiative Operation Warp Speed, Dr. Moncef Slaoui told ABC News' Bob Woodruff this week that if a vaccine is authorized before the end of the year approximately 20 million to 40 million doses of it will be stockpiled and ready for distribution for a limited population. At first, only high priority Americans, like those over 65, will have access, but by springtime more Americans should have access.
Slaoui said that vaccine trials are going as fast as it's safe to go, pledging to resign if he felt undue pressure from the White House. Slaoui said that by June 2021, it's possible "everybody" in the United States could have been immunized.
--Sony Salzman and Sasha Pezenik
Trump calls COVID-19 antibody treatment a 'cure.' It's not.
TRUMP'S CLAIM: "And I will tell you that I had something that they gave me, a therapeutic, I guess they would call it, some people could say it was a cure. But I was in for a short period of time and I got better very fast or I wouldn't be here tonight."
FACT CHECK: Trump also repeated something he has said before, praising the antibody treatment he received a "cure."
But as of yet, there is no known "cure" for the novel coronavirus.
The antibody cocktail given to the president -- made by biotech company Regeneron -- is thought to be promising, though still in its experimental phase.
Regeneron's experimental treatment is a cocktail of two synthetic, pharmaceutical versions of what occurs naturally in the body to fight off infection. Late last month, Regeneron published positive, yet preliminary data for its cocktail treatment showing it improved symptoms in patients without severe disease.
While the Food and Drug Administration has not yet authorized it, Trump was granted access to it under "compassionate use," enabling him to get it outside of a clinical trial.
A Regeneron spokesperson confirmed to ABC News that Trump's medical staff reached out to the company for permission to use its monoclonal cocktail, and that it was cleared with the FDA.
--Sony Salzman and Sasha Pezenik
Trump falsely claims that kids aren't transmitting virus to teachers
TRUMP'S CLAIM: "I want to open the schools. The transmittal rate to the teachers is very small."
FACT CHECK: The Centers for Disease Control and Prevention has updated its guidance to note a "body of evidence is growing" that kids "might play a role in transmission." Still, the role children play in community transmission is not yet fully understood.
In one recent study, the CDC found transmission is unclear: "Recent evidence suggests that children likely have the same or higher viral loads in their nasopharynx compared with adults and that children can spread the virus effectively in households and camp settings."
Schools haven't been studied as closely because many remain closed and not every school is reporting outbreaks. One concern is that children might be transmitting the virus without exhibiting symptoms, and testing people without symptoms remains limited.
Overall, officials say the lower transmission levels in a community, the less likely schools will spread the virus.
Biden off on Trump's 'plan' that could defund Social Security
BIDEN'S CLAIM: "The idea that we're in a situation that is going to destroy Medicare, this is the guy that the actuary of Medicare said ... if, in fact, he continues to withhold -- his plan to withhold the tax on Social Security, Social Security will be bankrupt by 2023."
FACT CHECK: Biden’s claim is misleading on a number of fronts, but is rooted in an action Trump took and comments he made in August.
Trump signed an executive order in August that temporarily halted the collection of the payroll tax, a tax on wages split by workers and their employers. He subsequently asserted that he would like to permanently eliminate the tax.
In 2019, the tax financed 89% of Social Security. Workers and employers each contribute 6.2% of wages, while self-employed people pay the full 12.4%.
However, following Trump’s signing of the executive order, he has said publicly that he will draw from the government’s "general funds" to cover any lost funding for Social Security, a scenario the actuary accounted for in his response to the group of Democratic senators, telling them that the solvency of the program will be essentially unchanged if Trump follows through and actually proposes legislation akin to his public comments.
But since Trump issued his order, and despite Biden’s claims that Trump put forward a full-fledged "proposal," Trump and the GOP have not unveiled more detailed legislation on how they would prevent the elimination of the payroll tax from impacting the financial security of Social Security.
In late August, Democratic Sens. Ron Wyden, Bernie Sanders, Chris Van Hollen and Chuck Schumer sent a letter to the chief actuary of the Social Security program asking what the effect of eliminating the payroll tax would be. In response, the chief actuary said he was not aware of any "hypothetical legislation" that had been proposed. In simply responding to the scenario posed by Senate Democrats, he said the Social Security benefits program would be depleted of funds by 2023 if there's no additional stream of funding identified to offset eliminating the payroll tax.
What Trump has not said thus far is what programs could potentially be impacted by the redirection of funds from the government's general fund, only that he will protect Social Security benefits. The general fund finances the operations of the U.S. government, such as recording "funds received and distributed by the Department of the Treasury," and it "includes assets held by government-sponsored entities like Fannie Mae and the Internal Revenue Service."
Trump falsely claims COVID-19 'spikes' in Florida, Texas and Arizona are gone
TRUMP'S CLAIM: When asked how he would lead the country during the next phase of the pandemic, President Trump said that "there was a spike in Florida, and it's now gone. There was a very big spike in Texas, it's now gone. There was a very big spike in Arizona, it's now gone. And there are some spikes and surges in other places. They will soon be gone."
FACT CHECK: Although cases did "spike" and reach record levels in Florida, Texas and Arizona earlier this summer, then steadily decreased for a few months, cases in all three states have been on the rise for the last several weeks.
Since Oct. 1, the seven-day average of new cases has doubled in Arizona, according to an ABC News analysis of COVID Tracking Project data, recording an average of 880 new cases a day.
In Texas, more than 6,000 cases were reported on Thursday, increasing by 37% in the last two weeks, and in Florida, the seven-day average is still hovering at 3,300 new coronavirus cases a day.
Additionally, nationally, cases are not in fact, going away.
New cases have been rising rapidly for the last five weeks.
Since Sept. 12, the seven-day average of new cases has surged by 77.5%. Just in the last 10 days, the U.S. has reported eight days with over 50,000 new cases reported, and on Thursday, the U.S reported over 73,000 new coronavirus cases, the highest daily figure in nearly three months.
Biden says he doesn't think Trump hasn’t spoken to Putin about election meddling, but Trump has brought it up
BIDEN'S CLAIM: "And to the best of my knowledge, I don't think the president has said anything to Putin about [election meddling]. I don't think he's talking to him a lot. I don't think he said a word. I don't know why he hasn't said a word to Putin about it."
FACT CHECK: A smirking Trump, under pressure from members of Congress and his own intelligence community, did in fact tell Russian President Vladimir Putin at the "Group of 20" countries summit last year not to interfere in the 2020 election.
But Trump delivered the warning in a very casual way, playfully wagging his finger at Putin without making eye contact with him, saying, "Don’t meddle in the election please, don’t meddle in the election."
Trump also pressed Putin in his first G-20 summit meeting on interference in the 2016 election after intelligence officials confirmed Russian involvement in manipulating the election, according to then-Secretary of State Rex Tillerson.
"The president opened the meeting by raising the concerns of the American people regarding Russian interference in the 2016 election. Putin denied such involvement, as he has done in the past," Tillerson said at the time.
Trump claims Hunter Biden received $3.5 million from Russia, money that went to a firm with which Hunter Biden denies association
TRUMP'S CLAIM: "Joe got $3.5 million from Russia, and it came through Putin because he was very friendly with the former mayor of Moscow, and it was the mayor of Moscow's wife. And you got $3.5 million. Your family got $3.5 million. And, you know, some day you're going to have to explain why did you get $3.5 [million]."
FACT CHECK: In September, Senate Republicans unveiled the findings of their highly controversial investigation into the foreign business dealings of Joe Biden's son, Hunter Biden -- and specifically whether those endeavors ever influenced U.S. foreign policy.
As part of their report, Republicans highlighted an alleged $3.5 million wire transfer sent from Elena Baturina, the billionaire wife of the former mayor of Moscow, to a bank account tied to Rosemont Seneca Thornton LLC, a consultant group that the committee said was co-founded by Hunter Biden.
George Mesires, a lawyer for Hunter Biden, dismissed the claim outright as "false," adding that Hunter Biden "had no interest in and was not a 'co-founder' of Rosemont Seneca Thornton, so the claim that he was paid $3.5 million is false."
Hunter Biden was involved with Rosemont Seneca Partners -- not Rosemont Seneca Thornton, as the Senate Republicans claimed. The two are separate entities, according to Mesires.
Politico reported last month that Trump also sought to engage Baturina's husband, the former Moscow mayor, for business opportunities prior to his time in office.
--Luc Bruggeman and Allison Pecorin
Trump uses false facts to defend family separations
TRUMP'S CLAIM: "The children are brought here by coyotes and lots of bad people, cartels, and they're brought here and they used to use them to get into our country." // "They built cages. You know, they used to say I built the cages." // "They are so well taken care of. They are in facilities that are so clean."
FACT CHECK: Trump was defending his now-defunct policy known as "zero tolerance" that required every adult who crossed the border illegally -- even those traveling with their children -- be detained in a bid to deter border crossings.
The result was that thousands of children were separated from their parents in a matter of weeks. It was a major departure from past U.S. policy. In the Barack Obama and George W. Bush administrations, families were separated in rare instances, such as cases of serious crimes like drug trafficking.
An internal investigation later found that the administration struggled to keep track of the parents, many of whom had been deported. The White House says the parents were contacted and abandoned the children, who were placed with U.S. sponsors, usually family members. The American Civil Liberties Union countered that parents have not been found and contacted and therefore could not give up rights to their children.
Homeland security officials have said that "coyotes" are often used to transport the families for a fee. But there has not been widespread evidence of cases of people falsely presenting themselves as related, with border patrol documenting them as "family units."
Trump’s suggestion that "cages" were built by the Obama administration is correct. Obama had faced an influx of children both traveling alone and with families as a result of violence in Central America. And at one point, the Obama administration tried housing the families in special detention centers.
But after a federal judge in California ruled that the arrangement violated a long-standing agreement barring kids from jail-like settings for extended periods, even with their parents, the government began releasing families into the U.S. pending notification of their next court date.
In 2018, photos taken by The Associated Press and posted online by liberal activists suggested the children in steel fencing was Trump’s doing. The photos were actually from 2014 when immigration detentions became flooded with families.
Trump falsely accuses Biden of calling Black Americans 'super predators'
TRUMP'S CLAIM: "He's been in government 47 years. He never did a thing, except in 1994, when he did such harm to the Black community. And they were called, and he called them 'super predators.' And he said that. He said it, 'super predators.' And they have never lived that down."
FACT CHECK: It was then-first lady Hillary Clinton who used the phrase "super predators" in 1996, while expressing her support for the 1994 crime bill.
Both former Vice President Joe Biden and President Donald Trump have made past references to Americans being "predators."
In a speech from on the floor of the Senate in 1993, Biden said, "We have predators on our streets that society has in fact, in part because of its neglect, created." He added, "They are beyond the pale many of those people, beyond the pale, and it's a sad commentary on society. We have no choice but to take them out of society."
Trump, in his 2000 book "The America We Deserve," wrote several times about "predators."
"The perpetrator is never a victim," Trump wrote. "He’s nothing more than a predator, and there can be no excuses made for killing old ladies, beating old men, or shooting adolescents."
Trump added: "If I were in charge of things, life would be even tougher for these predators. If there was a situation in New York like that terrible dragging death in Texas, I’d not only put the perpetrators to death, I’d find some way to make them an example to others."
--Beatrice Peterson and Chris Donovan
US exports more energy than imports, but not completely energy independent, despite Trump's claim
TRUMP'S CLAIM: "We are energy independent for the first time."
FACT CHECK: The U.S. exports more energy products like oil and liquid natural gas than it exports, but many parts of the country still rely on oil from other countries.
But the U.S. is not fully energy independent.
The amount of oil produced in the U.S. is about 1.25 million barrels a day short of demand, according to the U.S. Energy Information Administration, and while imports are at a record low the country still relies on imported products for 3% of domestic petroleum consumption.
One of Trump's goals has been to make the U.S. energy independent, in part by expanding oil and gas drilling around the country including on public lands.
Last year, U.S. energy exports surpassed imports for the first time since 1952, largely due to increases in natural gas production.
Trump left out significant detail when saying 2.2 million Americans were initially expected to die from COVID-19
TRUMP'S CLAIM: "So as you know, 2.2 million people modelled out were expected to die."
FACT CHECK: It is true that, in the spring, one early model predicted more than 2 million deaths from the COVID-19 pandemic, although the model said the death toll would only be that high no attempts were made to control the pandemic.
During a March 29 White House coronavirus task force press briefing, Trump and White House coronavirus response coordinator Dr. Deborah Birx said that models showed up to 2.2 million people could die from COVID-19 in the United States "if we did nothing," as the president put it.
This was an estimate of potential deaths if neither the government, nor individuals, choose to alter their behavior, despite the pandemic.
The prediction may have been drawn from a model by Neil Ferguson, an epidemiology professor at Imperial College London, which found that an "unmitigated epidemic" could result in "2.2 million [deaths] in the U.S."
Trump wrong on COVID-19 mortality rates
TRUMP'S CLAIM: Trump said that "the mortality rate is down 85%" for COVID-19 in the United States, and that "the excess mortality rate is way down, and much lower than almost any other country."
FACT CHECK: Although Trump was correct to assert that death rates have fallen significantly since the spring, they are not down by 85%, but rather 62% -- and they are currently trending up again nationwide.
According to public health experts, much of that decline can be attributed to greater testing, better treatment protocols and to a larger number of younger people -- rather than older people -- becoming infected with COVID-19.
Meanwhile, "excess mortality" is an estimate of how many more people are dying than during a normal year, or other time period. It is incorrect to refer to the rate as "way down," since it is estimated that in the United States, there have been many more excess deaths compared to last year.
The Centers for Disease Control and Prevention reported on Tuesday 299,028 more people had died in the United States from late January to early October than would be expected in a typical year. It attributed 66% of those excess deaths, or 198,081, to COVID-19.
According to a report published in the Journal of the American Medical Association, "The U.S. has experienced more deaths from coronavirus disease 2019 (COVID-19) than any other country and has one of the highest cumulative per capita death rates."
Analyzing the number of deaths per 100,000 people attributed to the pandemic, the U.S. had 60.3 deaths per 100,000 people. That was higher than Germany (11.3), Canada (24.6) and France (46.6), but lower than Belgium (86.8) and the United Kingdom (62.6), according to the report.
This report was featured in the Friday, Oct. 23, 2020, episode of “Start Here,” ABC News’ daily news podcast.
"Start Here" offers a straightforward look at the day's top stories in 20 minutes. Listen for free every weekday on Apple Podcasts, Google Podcasts, Spotify, the ABC News app or wherever you get your podcasts.