Harvard Law School professor emeritus Alan Dershowitz told CNN’s Don Lemon on Tuesday night that President Donald Trump was well within his rights to fire former FBI director James Comey, and that there was no need for a special prosecutor in the investigation into possible collusion between Russia and the Trump campaign.

Dershowitz questioned the timing of Comey’s firing, however, and urged a new, independent investigation into the Russia case.

Dershowitz appeared next to CNN legal analyst Jeffrey Toobin, who was apoplectic. “The fact that he did this will disgrace his memory for as long as this presidency is remembered. There is only one date that will be remembered after Januarth 20th so far in the Trump presidency, and it is the day of the ‘Tuesday Night Massacre,'” Toobin said, referencing President Richard Nixon’s firing of Special Prosecutor Archibald Cox during the Watergate scandal.

Toobin had also told CNN’s Anderson Cooper earlier that Trump would likely name a “campaign stooge” as Comey’s replacement at the FBI.

But Dershowitz disagreed.

“Should Comey be the director of the FBI? The answer to that is no,” he said, noting that he had called earlier for Comey to resign. “He lost his credibility. … A lot of this is his fault.”

Dershowitz said there were three more questions to address.

“The second question is: should it be the President of the United States who makes the decision to fire him? Not while he’s under an investigation,” Dershowitz said (though Trump is not actually under investigation, a point he stressed in firing Comey).

The third question, Dershowitz said, is “who he appoints next.” He disagreed with Toobin: “If he appoints a man or a woman of great integrity, this date will not go down … in history because we will have been proved wrong that it was some kind of a cover-up if he picks somebody who can pursue the investigation.”

Fourth, Dershowitz suggested that Congress establish an independent commission — “not a special prosecutor, there is no probable cause” — to continue the Russia investigation.

When Toobin objected that Trump had fired former Acting Attorney General Sally Yates and former U.S. Attorney Preet Bharara as well as Comey, “all three of whom had the potential to investigate and trouble the Trump presidency,” Dershowitz argued that they were all Democrat appointees and had all been dismissed appropriately by a Republican president.

Former federal prosecutor Laura Coates chimed in that while she did not believe Trump fired Comey for the reasons he stated, Comey had given President Trump reason to fire him.

Comey “was wrong to usurp the role of the Attorney General,” she said, and noted that he had justified doing so again last week in testimony before Congress.

Host Don Lemon pushed back against Dershowitz and Coates, noting that he agreed with Toobin that the simpler explanation — that Trump was trying to cover something up — was more likely.

Joel B. Pollak is Senior Editor-at-Large at Breitbart News. He was named one of the “most influential” people in news media in 2016. He is the co-author of How Trump Won: The Inside Story of a Revolution, is available from Regnery. Follow him on Twitter at @joelpollak.