Don Lemon startled some colleagues on CNN’s morning show Thursday with his implication that Republican presidential candidate Nikki Haley, at age 51, was past her prime.

Lemon, with “CNN This Morning” co-hosts Poppy Harlow and Kaitlan Collins, was discussing Haley’s suggestion a day earlier that politicians over age 75 should be subject to mandatory mental competency tests. President Joe Biden is 80 while another GOP presidential candidate, former President Donald Trump, is 76.

“Nikki Haley isn’t in her prime, sorry,” Lemon said, explaining why he was “uncomfortable” with the age discussion. “When a woman is considered to be in her prime — in her 20s, 30s and maybe her 40s.”

“Prime for what?” Harlow replied.

Lemon said that if you look it up on Google, a woman is considered to be in her prime at those ages. Harlow tried to clarify what Lemon was referencing: “I think we need to qualify. Are you talking about prime for childbearing or are you talking about prime for being president?”

“Don’t shoot the messenger, I’m just saying what the facts are,” Lemon replied. “Google it.”

He brought up the subject again an hour later, when commentator Audie Cornish joined the discussion. Like Harlow had earlier, Cornish said the idea of “prime” that Lemon was referring to was about reproductive years, and didn’t concern mental health and aging.

“She’s in her prime for running for office,” Cornish said of Haley, who announced her candidacy Tuesday. “Political prime is what we’re talking about.”

Later Thursday, Lemon issued a statement saying he regretted his “inartful and irrelevant” references to a woman’s prime age.

“A woman’s age doesn’t define her either personally or professionally,” he wrote on Twitter. “I have countless women in my life who prove that every day.”

There was no immediate comment from CNN leaders. CNN chief executive Chris Licht launched the network’s new morning show in November.

Haley tweeted out a video of the CNN exchange on Thursday, saying “liberals can’t stand the idea of having competency tests for older politicians to make sure they can do the job. BTW, it’s always the liberals who are the most sexist.”

Haley also retweeted other anti-Lemon comments from conservative politicians and media figures, and moved quickly to take political advantage.

She emailed a fundraising appeal to supporters, decrying Lemon as a “CNN liberal,” including a link to the clip.

“We must fight these liberal attacks,” Haley’s campaign wrote. “They hate conservative women the most.”

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