Charles Krauthammer spoke on "The Kelly File" about "the collapse of Donald Trump" at the Fox News Republican debate.

He said Trump, for the most part, had "no substance" in his answers, particularly on a new report about an Iranian general's trip to Russia.

"He didn't have a clue [on that question]," said Krauthammer, adding that Trump dodged questions and appeared "thin-skinned" at times.

"It shows, for all the anti-politician atmosphere in the country, the value of knowing the issues and being a practiced speaker," he said.

Krauthammer said he's not sure whether the performance will hurt Trump's poll numbers, adding that Trump does much better when he can "ramble" freely.

"He was out of place," Krauthammer said. "Here, when he was controlled in a tight setting, he was lost for most of the debate."

Krauthammer said Ben Carson looked "relatively weak" for most of the night, but redeemed himself with a "brilliant closing statement."

Overall, Krauthammer's winners of the night were Marco Rubio, Mike Huckabee, Ted Cruz and Chris Christie for "besting" Rand Paul in a heated exchange on the NSA.

Watch his thoughts below.

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