The FBI raid on President Donald Trump's personal attorney "is an epic battle for the soul and cooperation of Michael Cohen," and prosecutors have "enormous weapons" to "pressure and coerce a witness," civil liberties expert Alan Dershowitz said Sunday.

"Oh, it's a very serious threat," Dershowitz, Harvard professor emeritus, told ABC's "This Week." "This is an epic battle for the soul and the cooperation of Michael Cohen. And prosecutors have enormous weapons at their disposal.

"They can threaten him, essentially, with life imprisonment. They can threaten his parents. They can threaten his spouse. They have these enormous abilities to really put pressure and coerce a witness."

President Trump might hold the trump card, though, Dershowitz said.

"On the other hand, the president has a unique weapon that no other criminal defendant or suspect ever has: He has the pardon power," Dershowitz added. "And go back to Christmas, 1992, when President [George H.W.] Bush exercised that pardon power and pardoned Casper Weinberger."

Dershowitz's remarks came one day after President Trump tweeted a series of his own on the topic Saturday.

The New York Times and a third rate reporter named Maggie Haberman, known as a Crooked H flunkie who I don’t speak to and have nothing to do with, are going out of their way to destroy Michael Cohen and his relationship with me in the hope that he will “flip.” They use.... — Donald J. Trump (@realDonaldTrump) April 21, 2018

....non-existent “sources” and a drunk/drugged up loser who hates Michael, a fine person with a wonderful family. Michael is a businessman for his own account/lawyer who I have always liked & respected. Most people will flip if the Government lets them out of trouble, even if.... — Donald J. Trump (@realDonaldTrump) April 21, 2018