EXCLUSIVE: Former Secretary of Education William Bennett — once an ardent supporter of Donald Trump — says he will not back the former president in his 2024 run for the White House because he does not believe he can win.

"I was a very strong supporter of [Trump] and defended him in lots of public forums, including Fox, however I hope he's not the nominee this time," Bennett told Fox News Digital on Wednesday.

The comments from Bennett, who served at the helm of the Department of Education under President Ronald Reagan and director of the Office of National Drug Control Policy under President George H. W. Bush, came after Trump announced Tuesday evening that he would make a third run for the White House in 2024.

"First of all, gratitude for the kind of country he ran. Our borders were secure, we were safe, the economy was humming for everybody, interest rates were low, and attention was being paid to the right things," Bennett said of Trump's time in the White House. "He ran a great country and policy trumps personality, but we've reached a point, and this is a calculation on my part, there are just too many people now who will not vote for Donald Trump."

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Bill Bennett, Trump

President Donald Trump, right, speaks next to Bill Bennett during the Faith and Freedom Coalition's Road to Majority conference in Washington, D.C., on June 26, 2019. (Andrew Harrer/Bloomberg via Getty Images)

"We all know a lot of people who say, ‘No matter what, I can’t vote for Trump,' and a lot of those people are the people who decide elections. They're the people in the middle — independents, moderates," he added. "That's just the way it is. I have great sympathy for Trump… So much of what he did was great, some of what he did was not so great. But I'm thinking about the country."

Bennett, currently a Fox News contributor, said he is looking for the type of leadership offered by individuals like Florida Gov. Ron DeSantis and former Secretary of State Mike Pompeo.

"I think a generation change is needed as well," Bennett said. "Both political parties could use a generation shift… We need to make that change."

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"I don't want to see [Trump] run and be defeated, which I think would happen in '24," Bennett added. "He ran a great country, he's got a great legacy in that. He should embrace that legacy and step aside."

Bill Bennett

"Both political parties could use a generation shift," said former Education Secretary Bill Bennett. (David Paul Morris/Bloomberg via Getty Images)

Bennett also said Trump's recent remarks about DeSantis and Virginia Gov. Glenn Youngkin, two Republicans who are rumored to seek the GOP presidential nomination for 2024, are "entirely inappropriate, wrongheaded and undeserved."

At a rally earlier this month, Trump mocked DeSantis and referred to him as "Ron DeSanctimonious" in what appears to be a sign of growing tension.

"DeSantis has done a great job — there's no question," Bennett said, pointing to the Republican trend in Florida. "It's pretty hard to argue with the record."

"We don't need this," Bennett said of Trump's comments targeting other prominent leaders of the GOP. "Plus, you know, he cost us the two Senate seats in Georgia… told people not to vote. He says he's going to Georgia and he'll be supporting Herschel Walker and telling people to vote. I hope that's the case. I hope he doesn't talk about himself, but talks about Herschel, but I have my worries."

DeSantis/Trump split

Former President Donald Trump, left, and Florida GOP Gov. Ron DeSantis (Joe Raedle/Getty Images | Giorgio Viera/AFP via Getty Images)

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During Trump's presidency, Bennett defended Trump on a number of fronts and commended him for his "America first" policies. In August, Bennett said the FBI raid on Trump's Mar-a-Lago estate in Palm Beach, Florida, was a "terrible thing" and insisted it was "unprecedented."

"Unprecedented to raid a former president's home — not just the compound, but his home," Bennett said at the time. "I doubt that's ever been thought of before in American history. And no sense of burden of why it happened, why they did it. No sense of explanation."