>>RELATED: Donald Trump's remarks on gun rights spark controversy
But on Monday night, Hillary Clinton's camp accepted the debates and challenged Trump to do the same.
On Tuesday, Trump also told Time, "certain moderators would be unacceptable." We're guessing he might be talking about Fox News' Megyn Kelly.
"She had blood coming out of her wherever," Trump said of Kelly in 2015.
Trump sitting out of a debate wouldn't be a huge surprise.
He did, after all, refuse to show up to one of the Republican primary debates.
If Trump refuses to debate during the general election, it would be the first time that's happened since 1972.
This video includes an image from Getty Images and clips from Donald J. Trump for President, Hillary for America, Fox News and C-SPAN. Music provided courtesy of APM Music.