Harvard law professor Alan Dershowitz said Sunday that both President Trump Donald John TrumpBiden on Trump's refusal to commit to peaceful transfer of power: 'What country are we in?' Romney: 'Unthinkable and unacceptable' to not commit to peaceful transition of power Two Louisville police officers shot amid Breonna Taylor grand jury protests MORE and his former campaign chairman, Paul Manafort Paul John ManafortOur Constitution is under attack by Attorney General William Barr Bannon trial date set in alleged border wall scam Conspicuous by their absence from the Republican Convention MORE, "acted too late" to avoid the possible consequences of Manafort's cooperation with special counsel Robert Mueller Robert (Bob) MuellerCNN's Toobin warns McCabe is in 'perilous condition' with emboldened Trump CNN anchor rips Trump over Stone while evoking Clinton-Lynch tarmac meeting The Hill's 12:30 Report: New Hampshire fallout MORE's investigation.

"Manafort, if he was going to make a deal, should’ve made it before he was convicted. He would’ve gotten a better deal," Dershowitz said on NBC's "Meet the Press."

"And President Trump, if he was going to pardon, he should’ve pardoned before Manafort agreed to cooperate," he added. "So there’s not going to be any pardon now, and Manafort has a deal. His sentence will reflect how much cooperation he gives."

ADVERTISEMENT

Dershowitz, who is an opinion contributor for The Hill, said it was possible that Manafort was acting on his own to make money when he communicated with Russian officials during the 2016 campaign. Even so, he noted that Manafort's decision to cooperate with Mueller marked a "very bad day for the Trump administration."

Manafort, who was convicted last month in Virginia on charges of bank and tax fraud, pleaded guilty on Friday to two federal charges and reached a deal to cooperate with Mueller and avoid a second trial on additional charges in Washington, D.C.

The deal includes an agreement to cooperate "fully and truthfully” with the special counsel.

Dershowitz on Friday called Manafort's guilty plea a "big win" for Mueller's investigation. "Potentially, [Manafort's guilty plea] opens up lots of doors that probably haven't been opened before," he said.

Manafort’s cooperation with Mueller could be significant to Mueller's investigation, given his work on the Trump campaign.

The White House and Trump's attorney, Rudy Giuliani, have downplayed the potential impact Manafort's deal may have on the president.

Trump's lawyers and Manafort's legal team had a joint defense agreement, meaning the two sides shared information. Giuliani declined to comment on whether a pardon was possible for Manafort, though he has said in the past such an offering would come after Mueller's investigation is ended.

Manafort is the fourth former Trump associate to reach an agreement to cooperate with Mueller, joining Michael Flynn, Richard Gates and George PapadopoulosGeorge Demetrios PapadopoulosTale of two FBI cases: Clinton got warned, Trump got investigated Trump says he would consider pardons for those implicated in Mueller investigation New FBI document confirms the Trump campaign was investigated without justification MORE.