President Joe Biden made several verbal missteps Thursday in the opening minutes of his debate with his Republican rival, Donald Trump, as both took the stage seeking to define their presidential rematch.Related video above: Security measures in effect for CNN Presidential debate in AtlantaBiden had a raspy voice, struggling repeatedly to clear his throat, and had a halting delivery as he tried to defend his economic record and criticize Trump. Biden appeared to lose his train of thought while giving one answer, drifting from an answer on tax policy to health policy, at one point using the word "COVID," and then saying, "excuse me, with, dealing with," and he trailed off again.Sources familiar with his debate preparations say Biden has been battling a cold in recent days, causing his voice to sound hoarse and raspy during the debate, even more so than usual. "Look, we finally beat Medicare," Biden said, as his time ran out on his answer.Trump picked right up on it, saying, "That's right, he did beat Medicaid, he beat it to death. And he's destroying Medicare."Trump falsely suggested Biden was weakening the social service program because of migrants coming into the country.Biden, the 81-year-old Democratic incumbent, entered the debate with the chance to reassure voters that he's capable of guiding the U.S. through a host of challenges as he moved to sharpen the choice voters will face in November. Trump, 78, had the opening to try to move past his felony conviction in New York and convince an audience of tens of millions that he is temperamentally suited to return to the Oval Office.Trump and Biden entered the night facing stiff headwinds, including a public weary of the tumult of partisan politics and broadly dissatisfied with both, according to polling. But the debate was highlighting how they have sharply different visions on virtually every core issue — abortion, the economy and foreign policy — and deep hostility toward each other.The two candidates strode on stage and walked directly to their lecterns, avoiding a handshake. The debate did not start with any of the fiery exchanges that defined their first meeting on the debate stage in 2020. Instead, each man stayed relatively measured as he defended his record and blamed the other for steering the country off track.Biden, pressed to defend rising inflation since he took office, pinned it on the situation he inherited from Trump amid the COVID-19 pandemic. Trump assailed Biden's withdrawal of American troops from Afghanistan, saying, "It was the most embarrassing day in the history of our country's life."Biden said that when Trump left office, "things were in chaos." Trump disagreed, declaring that during his term in the White House, "Everything was rocking good."The current president and his predecessor hadn't spoken since their last debate weeks before the 2020 presidential election. Trump skipped Biden's inauguration after leading an unprecedented and unsuccessful effort to overturn his loss that culminated in the Jan. 6 Capitol insurrection by his supporters.Trump has promised sweeping plans to remake the U.S. government if he returns to the White House and Biden argues that his opponent would pose an existential threat to the nation's democracy.Thursday's broadcast on CNN, moderated by anchors Jake Tapper and Dana Bash, marked the earliest general election debate in history. It's the first-ever televised general election presidential debate hosted by a single news outlet after both campaigns ditched the bipartisan Commission on Presidential Debates, which had organized every matchup since 1988.Aiming to avoid a repeat of their chaotic 2020 matchups, Biden insisted — and Trump agreed — to hold the debate without an audience and to allow the network to mute the candidates' microphones when it is not their turn to speak. The debate's two commercial breaks offered another departure from modern practice, while the candidates have agreed not to consult staff or others while the cameras are off.Trump and his aides have spent months chronicling what they argue are signs of Biden's diminished stamina. In recent days, they've started to predict Biden will be stronger on Thursday, aiming to raise expectations for the incumbent.Biden's team too predicted that he would rise to the occasion, and expressed hope that Trump would be forced to address his positions they believe are anathema to voters."Joe's ready to go. He's prepared. He's confident," his wife, Jill Biden, told donors ahead of the debate. "You know what a great debater he is."Heading out of the debate, both Biden and Trump will travel to states they hope to swing their way this fall. Trump is heading to Virginia, a one-time battleground that has shifted toward Democrats in recent years.Biden is set to jet off to North Carolina, where he is expected to hold the largest rally of his campaign in a state Trump narrowly carried in 2020.