President Barack Obama and GOP candidate Mitt Romney will go head to head Wednesday night in the first presidential debate.
The debate will take place at the University of Denver.
The Kennedy-Nixon debates of the 1960s were the last debates to seriously impact election results, said University of Florida political science professor Stephen Craig.
"You can't prove that an election would have turned out differently without whatever debate moments there were that year," Craig said. "All you can do, really, is test for effects; get people to watch the debates and see if their attitudes changed as a result of that."
The effect of presidential debates on election results is fairly small, he said. Large numbers of voters don't change their opinion because of the debates.
Many people have already decided who to cast their ballots for, he said.
UF director of Forensics, Kellie Roberts, disagreed.
She said the Obama-Romney debates could be very influential on voters.
"In the past, these debates have not been that big of a deal," she said. "People watch them mainly to kind of strengthen what they already believe, strengthen the vote that they already know they're going to make."
She said this election involves a significant amount of people who haven't made up their minds yet.
Wednesday's debate could make a difference for undecided voters, she said. Details like President Obama's mannerisms might be enough to sway viewers to one candidate's side.
Romney's task is to put the president on the defense, she said.
Craig agreed that President Obama would be under a lot of scrutiny during the debates.
"The president's going to have to defend himself and his record," Craig said.
Katherine Hahn edited this story online.