Ahead of tonight's presidential debate, a first opportunity to see former Vice President Joe Biden and President Trump spar over a range of critical issues, some voters already decided who they are voting for.

At least 1.1 million ballots have already been cast in the 2020 election, according to data compiled by Michael McDonald, an elections expert and professor of political science at the University of Florida.

Across the 14 state reporting data -- Minnesota, Michigan, Wisconsin, Florida, North Carolina, Georgia, Ohio, Iowa, Illinois, Virginia, South Carolina, Montana, South Dakota and New Jersey -- voters cast a total of 1,144,059 ballots, as of the most recent reports.

McDonald cautions that the total number is likely higher because he does not "have complete reports for all states."

On Sunday, when the vote total was just under 1 million, McDonald wrote in his analysis that the volume of early voters "this far in advance of an election has never occurred in any American election. Period."

"Around this time in 2016, I noted only 9,525 people had voted," he wrote. "There literally is no comparison since at this comparable point in time in 2016, so few people had cast early votes that states did not bother to release any data."

-ABC News' Kendall Karson

The horrific killing of George Floyd in March set off massive protests across the country against racial injustice and police brutality.

Over the months that followed, new and previous supporters of the Black Lives Matter (BLM) movement held demonstrations from coast to coast and a new generation of Americans protested for racial equality.

Race is now at the center of the national conversation heading into the final weeks of the 2020 campaign for president, from the disproportionate impact the novel coronavirus pandemic has had on communities of color to reforms that would help address racial disparities in policing.

It has also been a complicated issue for both candidates over the course of their long careers. Former Vice President Joe Biden made history by choosing a Black woman, Kamala Harris, to be his running mate and served alongside the nation's first Black president.

But he has also drawn criticism for his position on busing in the 1970's to help end segregation in schools and the 1994 crime bill, which helped lead to an era of mass incarceration.

Trump set the tone for his presidency when he said Mexico was not sending its best immigrants, including "rapists," on the day he announced his campaign. That was followed by a call to ban Muslim immigration, his perpetuation of the debunked "birther" conspiracy against President Barack Obama among other things. And he has largely ignored the sources of the racial unrest that has erupted around the country in recent months.

At the same time, Trump has claimed he is the least racist person and touted the economic opportunities he has created for African Americans during his presidency.

Here's a look at where Trump and Biden differ on the issue of racial justice, and significant statements they’ve made related to race

-ABC News' Justin Gomez

The FiveThirtyEight presidential election forecast has Joe Biden with a 78 in 100 chance of winning the Electoral College -- but the outcome is a long way from certain.

Check out some of FiveThirtyEight's debate and election content here:

Will the first presidential debate shake up the race?

Who will win the first 2020 presidential debate?

Election forecast

How to vote in the 2020 election

President Trump had planned to meet with a small team of advisers over the weekend to go over to go over topics ahead of Tuesday night's faceoff, sources familiar told ABC News.

Over the last few weeks the president has resisted typical debate prep, similar to 2016. This time, debate meetings have taken place both at the White House and the president's weekend retreat in Bedminster, New Jersey, with sessions often including top advisers such as former New Jersey Gov. Chris Christie, Trump campaign manager Bill Stepien, Jason Miller and Jared Kushner along with other top aides.

The sessions have often featured conversations about potential debate topics or issues of the day that are on the president's mind with few traditional sessions such as mock debates, according to sources familiar with the meetings.

Trump has also been eager to target Biden personally, looking to lean into attacks on his son, Hunter Biden, once he's on the debate stage, including over his Ukraine business dealings while his father was in office, though he has denied any wrongdoing and has never faced charges, sources said. The president even previewed that strategy at a rally Fayetteville, North Carolina, laying into the former vice president's son and saying, "I think it'll be brought up in the debate."

-ABC News' Will Steakin, Katherine Faulders and John Santucci

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.