The vice presidential debate on Tuesday between Republican Indiana Gov. Mike Pence and Tim Kaine, a Democratic U.S. senator from Virginia, has the potential to elevate one of the contenders as a valuable asset to their staffs or serve as detrimental sound bite for their rivals.
Either way, one candidate will walk off that stage uplifting his team or quickly diminishing his role in the campaign, said Joel Goldstein, the country's premier scholar on the office of the vice presidency at the University of St. Louis School of Law.
"Representing the candidate in a debate as the vice-presidential pick is a pretty tough assignment," he said.
"You are not only talking about your views, but you really have to be conversational about the views and biographies of your candidate, defend them as well as yours and be able to effectively attack the views and biography of the other two."
They were picked just two months ago — and they now have to walk a fine line, Goldstein said.
"It is a high-pressure kind of situation and a lot of information to not only store, but be able to use to your advantage.
"If you don't do well you not only hurt the candidate, but also yourself," he added. "But if you hit it out of the park, well, then, you are an invaluable asset."
Goldstein has written two books on the vice presidency.
Pence and Kaine will debate at Longwood University in Farmville, Va.
The contest comes eight days after the first presidential debate between Donald Trump and Hillary Clinton, which experts agree the Democratic nominee won on points.
Kaine, 58, will be performing in a state where he has served as governor and where he is one of two Democratic senators.
He was considered a safe pick by Clinton.
The choice was criticized by some progressives, who were looking for a younger minority choice because of Kaine's potential inability to excite blacks, Hispanic and millennials — groups the former secretary of state is struggling to motivate.
The calculous was that Kaine would keep Virginia blue in a tight race.
Pence, 57, is a former leader in the U.S. House and is a vocal social conservative. His pick was considered wise for his establishment credentials and broad support among evangelical voters.
Up until this point, both vice presidential candidates have been overshadowed by the uniqueness of both of the nominees — something that might change after Tuesday.
In 1976, Republican Bob Dole and Democrat Walter Mondale appeared in the first debate between vice presidential candidates.
"Because it was the first debate, it was awkward — with neither really knowing what their role was supposed to be," Goldstein said. "But after a while, Mondale took advantage of Dole's lack of focus and his sarcastic remark about Democrats always starting wars and was perceived to have won the debate.
"The next day, Mondale was elevated in the campaign," he added. "It is one of the relatively rare times that a vice presidential debate has truly elevated someone to such a high level."
Goldstein said that other memorable moments have occurred during vice presidential debates over the years that made news but did not affect the race.
"Dan Quayle was actually having a very good debate against Lloyd Bentsen in 1988, but Bentsen seized on his obvious sensitivity about experience," he began. "And when he referenced a comparison not to JFK personally, but to JFK's congressional years of service, Bentsen delivered that famous line:
"'Senator, I served with Jack Kennedy. I knew Jack Kennedy. Jack Kennedy was a friend of mine. Senator, you're no Jack Kennedy.'
"That haunted Quayle," Goldstein said.
"Bush-Quayle still beat Dukakis-Bentsen, but that line stuck."
Goldstein listed other memorable debates: George H.W. Bush and Geraldine Ferraro (first woman) in 1984; Dick Cheney and John Edwards in 2004 (Edwards' remarks about Cheney's daughter's sexuality); and Joe Biden and Sarah Palin in 2008 (attracted more viewers than the debate between candidates John McCain and Barack Obama).
Salena Zito covers national politics for Newsmax.