President Trump is on his way to Ohio ahead of the debate tonight and while he didn't speak to reporters before departing, his chief of staff Mark Meadows said that Trump was essentially done preparing for the debate and added that he was in a good mood.

Meadows said that some of the debate guests would be traveling on Air Force One, but didn't name names. However Alice Johnson, who Trump pardoned last month, was spotted boarding.

In addition to Johnson, the pool traveling with the president so far has spotted Lara Trump, Eric Trump, Tiffany Trump, Donald Trump Jr. and Kim Guilfoyle aboard Air Force One.

-ABC News' Katherine Faulders

Despite Republican successes in statewide races in Ohio since 2016, the Buckeye State has become increasingly competitive as Trump and former vice president Joe Biden prepare to face off in Cleveland for their first debate on Tuesday.

In recent weeks Trump and Vice President Mike Pence have traveled repeatedly to Ohio, where they defeated Hillary Clinton and Sen. Tim Kaine, D-Va., her vice presidential candidate, in 2016, 51% to 43%.

Republicans also performed well statewide two years ago, winning the gubernatorial race and other down-ballot contests.

“Ohioans showed up for President Trump in 2016 and we expect them to do the same this November,” Trump campaign spokeswoman Samantha Zager told ABC News.

The president’s campaign has had a permanent presence on the ground in Ohio since 2016, and said they have made more than 10 million voter contacts in the state, where they and other GOP groups continue to canvass on the ground during the coronavirus pandemic.

The Biden campaign, meanwhile, has relied on virtual and digital organizing in the state during the pandemic, and has hosted hundreds of events and held 450,000 conversations with voters over the last month. Following Tuesday's debate, Biden will take a train tour of the state on Wednesday.

Biden has delivered a sharp economic message focused on Trump's record, centered on Toledo and Youngstown, home to several car plants and many blue-collar voters who abandoned Democrats and voted for Trump for years ago.

He's run at least eight television ads in recent weeks, including a response to Trump's call for a ban on Goodyear, the Ohio-based tire company than ran in Akron, where the company is based.

In an election year reshaped by the coronavirus pandemic, it’s also playing host to a number of legal battles over access to ballot drop boxes, which are increasingly used by voters as an alternative to in-person voting or relying on the United States Postal Service, amid concerns about service delays.

Read more about the battle for Ohio here.

-ABC News' Ben Siegel and Adia Robinson

An immutable fact of politics in the era of President Donald Trump is that there's no separating the president from his base.

Yet an ABC News/Washington Post poll released Tuesday morning out of critical Pennsylvania -- FiveThirtyEight's most likely tipping-point state -- brings new evidence that Trump can't bank on the range of supporters he once did.

The poll shows former Vice President Joe Biden leading Trump 54-45 among likely voters, mirroring the results of the ABC/Post national poll released Sunday. Hillary Clinton backers from 2016 support Biden 98-1 in the Pennsylvania poll, while Trump's supporters from last time break 92-8 in his favor.

This does not mark a mass exodus. But it suggests a narrowing coalition, Wisconsin and Michigan -- all states won by Trump by less than a percentage point, in a region Trump and Biden are set to visit in the days after Tuesday night's first presidential debate.

There won't be many, or perhaps any, singular moments as critical as this first debate in terms of changing the trajectory of the race. Trump wants and needs to effectively disqualify Biden as an alternative -- to make the campaign about Biden more than himself.

Biden will be trying to avoid a brawl of an insult-fest. He will be seeking to keep the campaign focused on COVID-19 and the economy -- about Trump and his leadership, in a campaign that's been more steady than not.

-ABC News Political Director Rick Klein

ABC News Chief Global Affairs correspondent Martha Raddatz joins ABC News' Start Here podcast to talk about her experience moderating debates with both President Donald Trump and former Vice President Joe Biden before the two go head-to-head for the first time Tuesday night.

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.