WATCH: Trump-defender Alan Dershowitz shocks with explanation that 'pardon is off the table' for Paul Manafort

Responding to news that former Trump campaign chairman Paul Manafort has entered into a plea deal with special counsel Robert Mueller, Harvard Law professor Alan Dershowitz explained why the prospect of a presidential pardon is now nil.

"Once [Manafort] agrees to cooperate, he has to cooperate about everything," Dershowitz told MSNBC host Steve Kornacki and his fellow panelists during the Friday segment. "There's no such thing as partial cooperation."

That cooperation, the Trump-allied attorney noted, is likely to eliminate any possibility of the president pardoning his former campaign chair.

"There will be no pardon," Dershowitz declared. "It will backfire at this point — if he's given a pardon then he can't take the fifth amendment, he would have to testify anyway. He could be called in front of a grand jury."

"The pardon is off the table," he concluded. "It's too little, too late."

Watch below, via MSNBC: