Both vice presidential nominees are seasoned debaters. During her ill-fated presidential primary bid, Harris participated in several debates and made headlines for her zingers, including a clash with Biden over busing to integrate schools. Expectations are high for her in the matchup against Pence, who hasn’t participated in a debate since 2016 but has held his own ground in the past.

In an interview with Hillary Clinton for her podcast “You and me Both,” Harris spoke about the challenges of preparing the debate, including her expectation that Pence could offer “a series of untruths” from the debate stage.

“I don't necessarily want to be the fact checker,” Harris said in the interview. “At the same time, you know, depending on how far he goes with whatever he does, he’s going to have to be accountable for what he says.”

Pence has called Harris a “skilled debater” and has told supporters at campaign events that he looks forward to being on stage with her, though he has remained mostly tight lipped about his expectations or how he’s been preparing for the matchup.

In 2016, Pence participated in the vice presidential debate against Sen. Tim Kaine and was seen to have successfully thwarted attacks over comments Trump made about women and Mexican immigrants, as well as his policy proposals.

During his debate against Kaine, Pence was disciplined, poised and polished and largely waited for his turn to get a response in.

-ABC News' Justin Gomez and Averi Harper

Two, five-foot tall plexiglass walls will stand between Vice President Mike Pence and Sen. Kamala Harris at Wednesday night’s debate.

The thick plastic barriers, approved by the Commission on Presidential Debates, will try to prevent the possible transmission of the coronavirus as Pence and Harris face off onstage for 90 minutes.

The Debate Commission said the plexiglass was part of a “variety of health safety protocols,” according to a factsheet. “Plexiglass will be used as part of the CPD’s overall approach to health and safety.”

Experts say that among the many protective measures put in place, the proposed plexiglass may not be the most effective option, particularly in light of updates from the Centers for Disease Control and Prevention to its guidelines on Monday acknowledging the potential for airborne transmission of the virus while indoors.

According to the CDC, it's possible for the virus to be transmitted beyond 6 feet by forming particles that can linger in the air for prolonged periods of time when infectious individuals “cough, sneeze, sing, talk, or breathe." The risk of airborne transmission is greatest in poorly ventilated indoor spaces as well as during prolonged exposure. Pence and Harris will be 12 feet apart from each other and from the moderator.

The clear dividers on stage could offer an added layer of protection, but it should not be a standalone measure, experts say.

More on experts concerns about safety protocols for the debate can be found here.

-ABC News' Sasha Pezenik and Ramie Fathy

Amid the controversy surrounding a plexiglass barrier at the vice presidential debate Wednesday, a number of Senate debates across the country have utilized the measures.

In last Friday's South Carolina debate, Democratic challenger Jaime Harrison brought his own plexiglass divider to his debate against Sen. Lindsey Graham.

Both candidates said they tested negative the day before the debate and those attending had to fill out a questionnaire saying they had no symptoms.

The Arizona Senate debate on Tuesday night also saw the candidates using plexiglass dividers.

In Colorado, Sen. Cory Gardner and Democratic challenger John Hickenlooper were separated with plexiglass dividers. Both candidates tested negative prior to the debate.

In North Carolina's debate last Thursday, plexiglass wasn't used, but Sen. Thom Tillis and challenger Cal Cunningham were socially distanced from each other and the moderator.

In Iowa, Theresa Greenfield and Sen. Joni Ernst shared a table with the moderators. All were separated by plexiglass barriers.

-ABC News' Meg Cunningham and Kendall Karson

Women's rights and advocacy organizations on the left have been working together to promote Harris's candidacy. This week they are gearing up too against what they fear will be sexist or otherwise biased attacks during the vice presidential debate Wednesday.

The long list of organizations, including BlackPAC, Color of Change PAC, EMILY's List WOMEN VOTE!, Planned Parenthood Votes! and UltraViolet say they are working in tandem on messaging and outreach. On the phone with ABC News, Shaunna Thomas, the head of UltraViolet, argued that female politicians are still more likely to face attacks -- subtle as they may be -- about their qualifications, trustworthiness and character. She said the coalition was planning to release content on social media and around neighborhoods Wednesday with an eye toward women of color in battleground states.

They want to underscore again the historic nature of the ticket.

"A lot of people are excited about this long overdue and historic moment for women of color and the whole country. Never has a woman of color served in such a position ... and it's time," she said.

The coordinated push comes as Biden again leaned into the issue of race and inequity in America on Tuesday during his event in Gettysburg, Pennsylvania.

"I think about what it takes for a Black person to love America that has a deep love for this country that has -- for far too long -- never been recognized," he said on the historic Civil War battlefield after talking about his conversations with the families of Black Americans whose loved ones have been killed by police.

-ABC News' MaryAlice Parks

PENCE'S CLAIM: "President Trump and I are fighting every day in courthouses to prevent Joe Biden and Kamala Harris from changing the rules and creating this universal mail-in voting that will create a massive opportunity for voter fraud."

FACT CHECK: Pence echoed Trump's attempts to cast doubt on the widespread embrace of vote-by-mail across the country this election by suggesting that universal mail-in voting could lead to massive fraud.

That is historically not true.

Kim Wyman, the Republican secretary of state in Washington -- a state that adopted statewide mail voting in 2011 -- told The New York Times in June that while any voting method could potentially be susceptible to fraud, in her experience as the chief elections official in the state, fraud with mail ballots is low.

"How do you respond to someone that makes an allegation that there's rampant fraud?" she said. "You show them all the security measures that are in place to prevent it and detect it if it does happen."

Ben Ginsberg, a Republican election guru who has spent years looking for voter fraud, wrote in a Washington Post op-ed, "Four decades of dedicated investigation have produced only isolated incidents of election fraud."

"These are painful conclusions for me to reach. Before retiring from law practice last month, I spent 38 years in the GOP's legal trenches. I was part of the 1990s redistricting that ended 40 years of Democratic control and brought 30 years of GOP successes in Congress and state legislatures. I played a central role in the 2000 Florida recount and several dozen Senate, House and state contests," he wrote. "The truth is that after decades of looking for illegal voting, there's no proof of widespread fraud."

Tom Ridge, a Republican who previously served as the governor of Pennsylvania and was the nation's first secretary of Homeland Security, previously told ABC News, "There is absolutely no antecedent, no factual basis for (President Donald Trump's) claim of massive fraud in mail voting."

--ABC News; Kendall Karson