What to know about tonight's debate President Joe Biden and former President Donald Trump held their first presidential debate of the cycle tonight in Atlanta. The two candidates were in a studio without an audience. Biden struggled at times, stumbling over answers with a raspy voice — a campaign aide said he has a cold — and adding fodder to concerns about his age and mental fitness. Near the halfway mark, Biden started gaining his footing again, mocking Trump's physical fitness and calling him a "whiner" and a "loser." Trump, meanwhile, offered numerous falsehoods and misleading statements in his responses. He hammered Biden on immigration and the border, even when he was asked about other issues. And he repeatedly dodged questions about whether he would accept the results of the election. Both candidates also hurled personal insults at each other, with Biden hitting Trump for his alleged affair with adult film star Stormy Daniels and Trump calling Biden a "complainer" and the "worst president" in American history.