Former Vice President Joe Biden boarded a new campaign plane in Wilmington, Delaware, at 3:18pm as he gets ready to head to Cleveland, Ohio, for the debate tonight.

-ABC News' Molly Nagle

Overwhelming support in Philadelphia and its suburbs lift former Vice President Joe Biden to a clear lead in crucial Pennsylvania, with backing from college-educated white people and women -- notably white, moderate and suburban women -- central to his advantage in a new ABC News/Washington Post poll.

President Donald Trump, for his part, is suffering attrition among his 2016 supporters; 8% of them now back Biden instead. While a small slice of the electorate, it’s a potentially important factor in a state Trump won by 44,292 votes out of nearly 6.2 million cast four years ago.

Likely voters support Biden over Trump by 54 to 45%, almost exactly matching a national ABC/Post poll released Sunday. The result includes more than a 2 to 1 Biden lead in the populous Philadelphia suburbs, home to nearly a quarter of likely voters, and close results in northeastern and western Pennsylvania, leaving only the conservative center of the state clearly to Trump.

See more data on this new poll here.

-Gary Langer of Langer Research Associates, conducted the poll.

-ABC News' Isabella Meneses contributed to this report.

The Biden campaign released Joe Biden and Kamala Harris’ 2019 tax returns, a clear effort to draw a sharp contrast with the revelations about Trump’s tax returns reported by the New York Times, ahead of tonight’s debate.

With Tuesday’s release Biden has made public 22 years of records, and Harris 15 years.

The releases were posted to Biden’s campaign site.

-ABC News' Mary Bruce and Molly Nagle

With unprecedented unemployment in the United States, where health care is inextricably linked to employment, and a coronavirus pandemic ravaging the globe, it's safe to say that on Nov. 3, health is on the ballot.

As it stands, more than 200,000 Americans have died of COVID-19. Another 13 million are unemployed.

Health might be a political football in 2020, but it's also a deeply personal issue that affects every American voter. Given health's crucial significance this year, the nonprofit Commonwealth Fund polled 4,220 likely voters in battleground states between Aug. 25 and Sept. 20 on which health care issues mattered most to them, and which candidate -- President Donald Trump or former Vice President Joe Biden -- they thought would be more likely to address those health concerns.

Here's what the American public said about which health care issues they care about, in advance of the first presidential debate.

-ABC News' Erin Schumaker

BIDEN'S CLAIM: Biden says 100 million Americans have pre-existing conditions, Trump says he's wrong

FACT CHECK: 100 million or more people have pre-existing conditions in the U.S.

Biden said during the debate that "100 million people" have pre-existing conditions, while Trump said that number was "totally wrong."

"There aren't 100 million people with pre-existing conditions," Trump said. The two candidates were debating about the path forward for health care in America.

Biden, who was arguing that Trump and Republicans would kick people with pre-existing conditions off of health care if they rescinded the Affordable Care Act, is correct that somewhere around 100 million Americans have pre-existing conditions, according to studies.

One study by the Health and Human Services Department in 2017 found that a large percentage of non-elderly Americans have pre-existing health conditions, ranging from 61 million to 133 million.

The study found that "at least 23 percent of Americans (61 million people) using a narrow definition based on eligibility criteria for pre-ACA state high-risk pools, or as many as 51 percent (133 million people) using a broader definition closer to the underwriting criteria used by insurers prior to the ACA" could have been denied health care or offered it at a high price before the Affordable Care Act passed because of pre-existing conditions. The study was published under the Obama administration.

There is a difference, however, between the absolute number of people with pre-existing conditions and the number of people who would be denied coverage under the Affordable Care Act. Experts point out that 54 million non-elderly Americans would've been denied insurance before the ACA, but confirmed that 100 million or more Americans have pre-existing conditions.

"54 million non-elderly adults have a pre-existing condition that would have led to a denial of insurance before the ACA. 100 million or more have a pre-existing condition that would have led to higher premiums or limited benefits," tweeted Larry Levitt, executive vice president for health policy at the Kaiser Family Foundation, referring to a study by the organization.