Constitutional law professor Jonathan Turley said Wednesday on "America's Newsroom" that the plea deal reached by Michael Cohen with federal authorities is a "serious" matter for the president.

"If people don't think this is a serious development, then they haven't been paying attention. You have the president's lawyer implicating him in a federal crime. Even if that lawyer is Michael Cohen, that's a serious matter," he said.

Cohen admitted in a plea deal Tuesday that he committed campaign finance violations at the direction of Trump. He pleaded guilty to five counts of tax evasion, one count of making false statements, one count of making an unlawful corporate contribution and one count of making an excessive campaign contribution by paying hush money to women who claimed to have had affairs with Trump.

"If what Cohen said yesterday is true, then virtually everything he said for the prior year was a lie," Turley said on Wednesday, adding prosecutors would likely need other evidence to corroborate Cohen's allegations if the matter was presented to a jury.

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Cohen was once looked at as one of the president's most committed and loyal backers, even going so far as to say he would "take a bullet" for him.

Turley added that how President Trump responds to Cohen's implication will be important.

He said it should be "chilling" that the Justice Department's filed Cohen's statements, because it certifies that they believe what he said is true.

President Trump made his opinion on Cohen known on Wednesday via Twitter, suggesting nobody looking for a "good" lawyer retain his services.

If anyone is looking for a good lawyer, I would strongly suggest that you don’t retain the services of Michael Cohen! — Donald J. Trump (@realDonaldTrump) August 22, 2018

He added that Cohen's story was made up in order to "get a deal."

I feel very badly for Paul Manafort and his wonderful family. “Justice” took a 12 year old tax case, among other things, applied tremendous pressure on him and, unlike Michael Cohen, he refused to “break” - make up stories in order to get a “deal.” Such respect for a brave man! — Donald J. Trump (@realDonaldTrump) August 22, 2018

"It's like a bad movie," Turley said. "It's always ... the guy who professes absolute loyalty that turns on the main character."

Cohen’s attorney, Lanny Davis, said on "America's Newsroom" on Wednesday that his client changed his mind about cooperating with federal authorities after witnessing President Trump's actions at a July summit with Russian President Vladimir Putin.

Turley scoffed at the idea that Cohen had an "epiphany" that triggered him to testify against his former client.

Watch more above, and hear Davis' comments below.

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