US Presidential debates provide the crucial opportunity for candidates to make a "big difference" and influence voters but the history of debating is also littered with gaffes, from Richard Nixon's legendary "sweaty upper lip" to George H W Bush checking his watch.
With Hillary Clinton and Donald Trump gearing up for their final debate on Wednesday at the University of Nevada in las Vegas, Dean of the Austin Marxe School of Public and International Affairs at Baruch College, David Birdsell said the final debate is the "last known opportunity" to make a big difference but the candidates can also "injure themselves through a gaffe, a serious misstep of some sort".
"This is indeed the last scheduled opportunity for either candidate to make a big difference," Birdsell said.