Republican lawmakers on the House Judiciary Committee Monday attacked star witness John Dean’s credibility, citing his criminal record and history of attacking President Trump and other Republicans.

“Mr. Dean has made a cottage industry out of accusing presidents of acting like Richard Nixon,” Rep. Matt Gaetz, R-Fla., said.

Dean, the ex-White House counsel in President Richard Nixon's administration, was convicted of obstruction of justice after striking a deal to cooperate with the Watergate investigation. He has spent decades critical of the GOP and wrote a book in 2004 accusing President George H.W. Bush of acts “worse than Watergate.”

He frequently appears on CNN as a paid contributor, in which he's usually criticizing Trump.

Democrats invited him to serve as their lead witness in a hearing meant to scrutinize the special counsel Robert Mueller’s investigation into alleged Russian collusion with the 2016 Trump campaign.

But Republicans ridiculed his appearance.

“You are functionally here as a prop because they can’t impeach the president,” Gaetz said, referring to the public polling against impeachment and resistance from Speaker Nancy Pelosi to allow an impeachment inquiry.

Dean declined to tell Gaetz how much money he has earned through his GOP criticisms in books and on television. Dean said he didn’t know.

“It’s not by choice I’ve done a lot of this,” Dean said. “I’ve been dragged into this.”

House Judiciary Committee Chairman Jerry Nadler, D-N.Y., and other Democrats praised Dean as a key figure in helping the Watergate prosecutors and whose testimony was deemed truthful.

And Rep. Jamie Raskin, D-Md., recalled his father, left-wing social critic Marcus Raskin, being placed on Nixon’s enemies list. Rep. Raskin on Monday called Dean “a man of honor, a man of integrity, and a man who stands up to the truth.”

But Rep. Andy Biggs, R-Ariz., pointed out 19 discrepancies were discovered in Dean’s statements back during the Watergate investigation.

Democrats called on Dean to use his Watergate past to assess Trump’s actions to obstruct the Mueller investigation.

Nadler introduced Dean without mentioning either his criminal conviction or that his law license was revoked.

“He is most well known as a principal witness during the Senate Watergate hearing,” Nadler said. “Where his testimony was later fully corroborated as to its truthfulness by the revelations in President Nixon’s White House tapes.”

Rep. Jim Jordan, R-Ohio, read through a litany of negative comments Dean has made about Trump, including one in which he describes discussing Trump’s impeachment with Pelosi, D-Calif.

Biggs called Dean a convicted felon offering “conjecture and legal posturing,” offering dubious testimony.

“You are not the fall guy in the Watergate scandal,” Biggs told Dean. “The FBI referred to you as the master manipulator of the cover-up. The U.S. attorney’s office said you were at the center of the criminality.”

Biggs called the hearing a farce.

“So much of what you say seems very difficult to accept at face value quite frankly,” Biggs said.