Analysts say Republican Donald Trump and Democrat Hillary Clinton have some of the highest negative ratings in the history of presidential election polling.
For Trump, voters have questions about his demeanor and temperament. For Clinton, it's about trustworthiness. Her use of a private server during her time as secretary of state is something that still troubles many voters.
The two candidates have been in the public eye for decades, but political consultant Mike Dawidziak says a strong performance during the debate can still change some hearts and minds.
"It would be very difficult to think that most Americans don't already think they know everything there is to know, but the debates are those opportunities to show the American people something new, something different," Dawidziak says.
But both candidates are also deeply unpopular in many places.
"This is the first time in the history of polling that we have two candidates who are both over 50 percent negative," Dawidziak says.
Trump and Clinton both appear to have strong bases of support, but the election will be won or lost with independents and undecided voters. It's the candidate's job tonight to not only win those voters over, but also inspire them to show up and vote on Election Day.
That may be a challenge, considering the views of some voters.
"I don't see any good pick in this election," says Chris Cassese of Islip.
Donna Brazile, interim chairwoman of the Democratic National Committee, argues that in addition to disdain for the candidates, many folks have been turned off by politics, and politicians in general, for years.
"We've lost faith in government," Brazile says. "We've lost trust in our elected officials. Congress is as popular as a root canal."
Seaford Rep. Peter King, who is supporting Trump's presidential bid, also says he gets along well with Clinton. He's able to say nice things about both candidates, which he says is rare.
"Here you have two, totally different, divergent candidates -- ideology wise, personality wise," King says. "So that just adds to the division."