Some 39 percent said the debates will not help, and 11 percent said they did not know how the debates would affect them.
In a strong signal that most viewers will also be hoping the debates bring clarity, some 72 percent of respondents said they want to see moderators point out when a candidate says something that is untrue.
That included 73 percent of people who identified themselves as Trump supporters and 82 percent of those who said they back Clinton, according to the results.
"It helps the audience, particularly me, to recognize what's bull crap and what's real," said Harvey Leven, 63, a teacher from Farmington Hills, Michigan. "It's easy for the candidates to quote a statistic and people accept it."
Clinton currently leads in most national polls and holds critical advantages in key swing states like Ohio and North Carolina. The latest Reuters/Ipsos poll finds Clinton leading Trump nationally by 4 percentage points.
Clinton had seen her popularity dip in recent weeks after more questions arose about her family foundation and the use of a private email server while she was secretary of state.
'No' to name-calling
Many voters are hoping to see a relatively civilized debate, after months of mutual attacks between Trump and Clinton on the campaign trail. Trump has called for Clinton to be jailed for her handling of emails as America's top diplomat. Clinton has accused Trump of racism and of being temperamentally unfit for the Oval Office.
Of those polled, 61 percent said they are not interested in those kinds of attacks.