Atlanta, Georgia - Joe Biden and Donald Trump clashed sharply Thursday on their records on the economy, abortion, and immigration at a debate with enormous stakes as each candidate seeks an advantage in their tight race for the White House.

The unprecedented face-off between a current and former president was taking place far earlier than usual in the election cycle, an opening campaign salvo in a deeply polarized country still scarred by the chaos and violence of the 2020 election.

Biden (81) and Trump (78) did not shake hands as they stood at podiums at the CNN headquarters in Atlanta with no live audience and with their microphones muted as the other spoke to avoid interruptions.

Biden, who spent the week preparing at the Camp David presidential retreat, opened with a rapid-fire critique of his predecessor and stumbled several times with Trump quickly seizing on his phrasing.

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Biden, asked about stubborn inflation, said, "We got to take a look at what I was left when I became president, what Mr. Trump left me."

"We had an economy that was in free fall. The pandemic was so badly handled, many people were dying. All he said was not that serious – just inject a little bleach in your arm," he said, referring to Trump's advice during the Covid pandemic.

Trump, his voice notably stronger than Biden's, said that he led "the greatest economy in the history of our country."

"We have never done so well. Everybody was amazed by other countries were copying us," he said.

Biden shot back, "Well, look, the greatest economy in the world? He's the only one who thinks that."

Both men took heated jabs at each other. Biden cited accounts that Trump had described soldiers who died in the Normandy landing as "suckers" and noted his own son Beau, who served in Iraq and later died of cancer.

"My son was not a loser, was not a sucker. You're the sucker. You're the loser," Biden said.

Trump denied the remarks and repeatedly accused Biden of not being coherent in his remarks.

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He described Biden's withdrawal from Afghanistan as the "most embarrassing moment in the history of our country" and said it encouraged Russia to invade Ukraine.

Biden, however, noted that he was the first recent president who has not had soldiers at risk overseas.

Trump and Biden also locked horns over abortion and immigration, key issues for their respective bases.

Biden, attacking Trump for appointing justices to the Supreme Court who ended Roe vs. Wade, the decision that allowed abortion rights around the country, said, "It's been a terrible thing, what you've done."

Referring to women who have been raped, Biden said, "It's just ridiculous, and they can do nothing about it."

For many voters, the choice between the 81-year-old Biden, the oldest ever incumbent, and the 78-year-old Trump, now a convicted felon, is an uninspiring one – a dynamic both candidates need to counter.

There is certainly no love lost between the two candidates, and both sides agreed to debate rules aimed at minimizing the prospect of a shouting match.

There is no studio audience, depriving them of the momentum that comes from ginning up supporters, and microphones will cut out when a candidate's speaking time is over.

One candidate not on the stage is Robert F. Kennedy Jr., a member of the storied political dynasty who is running an anti-establishment campaign but failed to meet CNN's standard of reaching 15% in four national polls.

Kennedy, angered that he is off the stage, is instead spending the 90 minutes of the Biden-Trump faceoff taking questions on a livestream in what he calls "The Real Debate."

Ahead of the debate, both Trump and Biden have had missteps, stumbling over words or appearing muddled.

Trump is also engulfed in controversy over his inflammatory rhetoric, his recent conviction on 34 counts of falsifying business records, and fears he would weaponize the presidency to settle personal scores.