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.

TRUMP'S CLAIM: "And now, we're weeks away from a vaccine."

FACT CHECK: Most prominent public health experts have said that a vaccine will not be widely available until mid 2021.

The pharmaceutical company Pfizer has said they may have data from its late-stage trial by October. Moderna has said it could have data from its late-stage trial by November or December. From there, the data will need to be analyzed by the FDA to determine whether the vaccine is both safe and effective. Other companies in late-stage trials are further behind. AstraZeneca's late stage trial is still on hold, and Johnson and Johnson only just started its late-stage trial this month.

Even if a vaccine is authorized by the end of the year, that does not mean it will be widely available. At first, only limited supplies will be available, and they will be prioritized for the most vulnerable.

"By the time you mobilize the distribution of the vaccinations and you get the majority or more of the population vaccinated and protected, that's likely not going to happen until the mid- or end of 2021," Dr. Anthony Fauci, the nation's top expert on infectious diseases, told MSNBC's Andrea Mitchell earlier this month.

In a recent Senate hearing, CDC Director Robert Redfield echoed those sentiments, "I think there will be vaccine that will initially be available some time between November and December, but very limited supply, and it will have to be prioritized," but, he said, "If you're asking me when is it going to be generally available to the American public so we can begin to take advantage of vaccine to get back to our regular life, I think we're probably looking at late second quarter, third quarter 2021."

-- ABC News' Sony Salzman