They didn't shake hands and it got worse from there. Key moments in Biden-Trump debate

U.S. President Joe Biden and former U.S. president Donald Trump spent an hour and a halfThursdaytrying to convince Americanvoters that they're the best choice to be president for the next four years, but they also demonstrated that they don't respect one another.

The debate was a chance for voters to see how the presumptive nominees for America's two major political parties 81-year-old Bidenfor the Democrats and78-year-old Trump for the Republicans would fare when squaring off against each other. And they didn't have to wait long for that.

A coin toss decided where the two men would stand, and when they emerged on the stage,they went to their respective podiumswithout shakinghands, a move that set the tone for the evening.

Here's a look at some of the other key moments during the audience-free debate, hosted by CNN.

Biden sounds strained

Biden sounded noticeably hoarse from the start of the debate. That did not change for the remainder of the 90-minuteevent.

To account for the president'sstrained voice, the White House said during the debate that Biden had a cold.

Frozen moment

Early on, Biden spoke about his administration's actions on the economy and addressed how much tax wealthy people are paying in America but also appeared to freeze mid-sentence in what could be the defining moment of the debate.

Making reference to America's wealthiest individuals, Biden referred to the country's many"trillionaires," before correcting the reference to "billionaires."

WATCH | Trump pounces on Biden fumble:

Biden stumbles on health-care answer as Trump pounces

2 months ago

Duration 0:39

U.S. President Joe Biden appeared to lose his train of thought during a debate in Atlanta that aired on CNN with former president Donald Trump, saying, Look, we finally beat Medicare. Trump responded by saying, He beat it to death.

He then talked about how boosting the amount of taxes the wealthypay could be put toward various investments including in health care, finishing his comments with the words "if we finally beat Medicare."

In response, Trumppounced, saying,"Well, he's right, he did beat Medicare he beat it to death."

'You're the sucker. You're the loser.'

An infamous quoteabout America's war deadresurfaced during the debate, in which Trump reportedly made reference to "suckers" and "losers."

On stage, Trump denied having made the comments as he has in the past.

But the topic came up after Trump accused Biden of mistreating U.S. veterans and suggested his opponent apologize on this point.

Instead, Biden got personal, evoking his son, Beau, who served in Iraq before dying of brain cancer.

He told Trump, "My son was not a loser, was not a sucker. You're the sucker. You're the loser."

Ukraine, Putin and U.S. support for Kyiv

Trump was asked by CNN's Dana Bashwhether he agreed with terms Russian President Vladimir Putin has setfor ending the war in Ukraine including having Moscow keep control of any land it has captured duringthe war.

WATCH |Biden, Trump trade barbs over 'World War 3,' Putin and Ukraine:

Biden, Trump trade barbs over 'World War 3,' Putin and Ukraine

2 months ago

Duration 0:37

After former president Donald Trump accused U.S. President Joe Biden of 'driving us' to a third World War, Biden responded by saying a Trump election win would see Vladimir Putin's Russia overrun Ukraine. 'Right now, we're needed, we're needed to protect the world,' Biden said after referencing Article 5 of the NATO treaty.

Instead of answering the question, Trump responded with attacks on Bidenand soon turned tothe chaotic withdrawal ofU.S. forces from Afghanistan.

"I have never heard so much malarkey in my whole life," Biden said in response.

But Bash returned to the question and Trump eventually said Putin's terms were "not acceptable."

Trump also expressed criticism of the support the U.S. has provided for Kyiv and describedUkrainian President Volodymyr Zelenskyy as "the greatest salesman ever."

Trump then claimed that if re-elected he would have the Ukraine conflict settled"before I take office."

Biden responded by saying Putin is "a war criminal," and that hisaggression won't end at the Ukrainian border.

"Do you think he'll stop if he takes Ukraine?" Biden asked.

Oval Office octogenarians

Biden and Trump are also the two oldest people toseeka second term in the Oval Office and many voters have concerns about their ages.

Biden is already the oldest president in U.S. history. If victorious in November, he would head into a second term that would put him in his mid-80s by the end of those four years.Trump, meanwhile, would be 82 at the end of a potential second term.

Both candidates were asked about their ability to handle the job of president as octogenarians.

"First of all, I spent half my career being criticized being the youngest person in politicsand now I'm the oldest," said Biden.

"This guy's three years younger and a lot less competent," he saidbefore going on to defend his record as president.

When asked about his own age, Trump mentioned having taken both cognitive and physical exams when serving as president.

"I think I'm in very good shape," said Trump. "I feel that I'm in as good of shape as I was 25, 30 years ago."

Interruptions not a factor

Concerns about interruptions saw CNN set rules that included muting themicrophones of the personwho wasn't supposed to bespeaking.

The two men mostlyavoidedinterruptions Thursday unlike theirprevious debateback in 2020.