Candidates weigh in on deterring a Chinese invasion in Taiwan

Florida Gov. Ron DeSantis said he believes that someone younger than Donald Trump should be in the White House in 2024. But he declined to respond to a rival's question about whether he thought the former president was fit for office.

Answering a question from NewsNation’s Elizabeth Vargas about ads his campaign has been running that show Trump acting confused, DeSantis said, “I think we need to have somebody younger" and 80 years old is too old to be president.

"The idea that we are going to put someone up there that's almost 80 and there's going to be no effects from that — we all know that that's not true," DeSantis said.

The GOP candidate said the country needs a new generation of leaders and a president who can serve two terms.

When pressed specifically by moderators if Trump is mentally fit to be president again, DeSantis said, "we need to have somebody younger." 

He said the media was making a "big deal" about Trump's comment to Fox News that he would only be a “dictator” on the first day of his presidency, before pointing to areas where he didn't think Trump wielded enough executive authority as president, including on immigration and federal agencies.

Former New Jersey Gov. Chris Christie interjected and attacked DeSantis for not directly answering.

“You have to be willing to offend with the truth and answer the question: fit or unfit,” Christie said.

DeSantis replied that it wasn’t about offending Trump, but rather “pointing out do you want to elect somebody who will be older than Biden was" when he took office after winning in 2020.

“I don’t think he’s as bad as Biden was at all,” he added, referring to Trump. “But I do think that over a four-year period it is not a job for somebody that’s pushing 80.”

Some background: The questions of age and the extent to which voters should try to judge politicians’ mental cognition – and whether it should disqualify someone from public office – are boiling up as the 2024 election season gets underway.

Biden, who is the oldest-ever president at 81, launched a bid for reelection in April. And Trump, the current GOP frontrunner is 77, would be 82 by the end of a non-consecutive second term.

The advanced age of both men is doing nothing to quell their ambition and their mutual antipathy after 2020’s bitter campaign. But it also poses risks for both parties and has fueled calls that it’s time to move on from a pair born in the 1940s.

CNN's Stephen Collinson and Ali Main contributed to this post.

This post has been updated with more details on the back-and-forth between DeSantis and Christie.