Mitchell McKinney, Director of the Political Communications Institute at MU

The first presidential debate between Donald Trump and Joe Biden is tonight.

University of Missouri’s Director of the Political Communications Institute Mitchell McKinney says though studies show most viewers have already chosen a side, these debates could make a difference.

“There is a small slice, and generally our studies show this could be no more than five percent, two or three percent of those debate viewers will come away who had not previously committed to a candidate and will make a candidate choice, a voting decision,” McKinney told Missourinet.

McKinney says those few percentage points could have an impact in closely-contested states.

“When you drill down to those battleground states — and that’s where elections are won or lost here in the U.S. in terms of the electoral college — most of those state polls that there may just be a one or two-point lead for one candidate or the other. So I do think that these debates have the potential to be consequential,” he said.

While each candidate’s performance is not certain today, there are a few tactics viewers can expect, McKinney said. The pressure is on Biden to handle an aggressive, personal attack style.

“I can’t imagine much the president would do that we would think, ‘Oh my goodness, that’s outside the pale or beyond that we expect of this president at least. So, that’s giving him (Trump) some latitude in terms of performing in this debate. Again, turning to Joe Biden, how will he respond to this very aggressive president who is likely to treat Biden as Donald Trump did Hillary Clinton four years ago?”

McKinney says four years ago the Clinton-Trump debates set viewing records and were “the most conflictual debates in history.”

McKinney has consulted with the Commission on Presidential Debates on the development of the “town hall” debate format and how debates can be structured to better educate citizens on significant campaign issues.

“Interestingly, we had to create new categories. Usually, we will analyze an attack on is it an attack on an issue, a stance or is it a personal attack on candidates.  We added to that personal name-calling, taunting, ridicule of the opponent,” McKinney said

Fox News’ Chris Wallace will moderate tonight’s debate – at 8:00 p.m. Central.