Former National Security Advisor Michael Flynn wants immunity to testify in the congressional and criminal investigations into Russian meddling in the U.S. presidential election.

Flynn’s attorney said Thursday that the retired general is in discussions with the House and Senate intelligence committees, indicating he wants immunity from "unfair prosecution."

President Trump tweeted Friday that Flynn is right to seek immunity, claiming that the retired general is caught up in a “witch hunt” of “historic proportion.”

On "Special Report" tonight, Charles Krauthammer said that it's "not a good idea" for Trump to inject himself into the Flynn-immunity discussion.

"If the FBI or any of the committees think that Flynn can deliver Trump, they will grant him immunity," Krauthammer said, adding that if it comes down solely to Flynn protecting himself, them he won't be granted immunity.

"He's only useful to the extent that he gets the big fish. That's how it is in all of these investigations," Krauthammer said.

Watch more above.

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