1st presidential debate between Trump and Biden spirals into chaotic clash

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.

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Trump vs. Biden on the issues: Racial justice

An overview of the presidential candidates’ positions on various issues.

ABCNews.com

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:

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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

Russia's ongoing brazen efforts to interfere in the presidential election -- as they did four years ago -- remains a principal concern among national security officials, along with other adversaries including China. But unlike in 2016, the rapid and sweeping embrace of vote-by-mail in response to the coronavirus pandemic injects new uncertainty about election security, as millions prepare to vote in an alternative way.

Fueling those anxieties over mail voting, which is underway in several states, is President Trump’s unsubstantiated allegations of rampant fraud, even as dozens of state election officials tell ABC News that they have confidence in the system. His campaign against vote-by-mail throughout the cycle exceeds similar efforts he made in 2016, when he argued, without evidence, that voter fraud was the only reason Hillary Clinton won the popular vote. His own voting integrity commission found no evidence of that.

The integrity of this year's matchup between Trump and former Vice President Joe Biden has taken on an outsized role in the increasingly competitive political environment, as attempts to undermine confidence in the democratic process mount both from outside the country's borders and from inside the Oval Office.

Biden has attempted to combat Trump’s onslaught by pointing out that Trump himself has voted-by-mail in Florida from the White House.

Some elections experts argue Trump’s offensive against mail-in voting is a voter suppression tool, which could lay the "groundwork for contesting a close election if he loses, " wrote Rick Hasen, a professor of law and political science at the University of California, Irvine, and the author of "Election Meltdown: Dirty Tricks, Distrust and the Threat to American Democracy."

"The most benign explanation for Mr. Trump’s obsessive focus on mail-in balloting is that he is looking for an excuse for a possible loss to his Democratic opponent, Joe Biden, in November. The less benign explanation is that he is seeking to sow chaos to drive down turnout and undermine the legitimacy of the election," wrote Hasen,.

At the first presidential debate on Tuesday at Case Western Reserve University in Cleveland, Ohio, the two rivals are set to spar over the integrity of the election, one of the topics previewed by the Commission on Presidential Debates.

Here's what we know about the candidates' histories with and stances on the issue

-ABC News' Kendall Karson and Quinn Scanlan