Noted conspiracy monger Jerome Corsi claims to continue to be in cahoots with President Donald Trump, offering a new, potentially dubious account of a non-written joint defense agreement with the president’s legal team.

But according to legal experts, any joint defense agreement not put down to paper would be highly problematic at best and, in the words of one former federal prosecutor, “malpractice” at worst.

Since going public last week with a draft plea agreement from special counsel Robert Mueller, Corsi has claimed that Trump attorney Jay Sekulow took care to make sure that a joint defense agreement between the two parties was never put down to paper, and remained oral.

In an interview Monday with TPM, Corsi said that Aaron Zelinsky, a prosecutor on Mueller’s team, first approached his lawyer about the existence of a joint defense agreement with Trump.

“Zelinsky got word that we had this agreement with Jay Sekulow,” he said, recounting a supposed phone call between Zelinsky and his attorney, David Gray.

“I said wait a minute, call Zelinsky, but I don’t want Zelinsky misled – I want Zelinsky to understand that we’re acting as if we had this formal agreement in place, but we don’t, we are acting as if that were in place,” Corsi said.

Trump personal attorney Rudy Giuliani confirmed the existence of the agreement last week, but didn’t specify whether it was committed to paper.

In the TPM interview, Corsi suggested that his coordination with the White House continues. He said that he had directed his new attorney Larry Klayman (who once called for a coup against Obama) to give a copy of a so-called “complaint” against Mueller to Trump’s legal team in advance.

But attorneys that TPM spoke with said that it’s extremely unlikely that an “informal” joint defense agreement could serve to provide Corsi and Trump with the kind of protections a joint defense agreement is mean to establish or even exist at all.

“It’s an uphill battle to say that we had an agreement but we never reduced it to writing,” said Elie Honig, a former federal prosecutor at Lowenstein Sandler. “The question is, ‘What are you trying to hide here?”

Honig added that joint defense agreements are very common in “multi-defendant cases, because they enable multiple defendants to share confidences with each other without waiving privilege.”

The former prosecutor added that while he had encountered cases involving non-written defense agreements, they mostly came from situations where there was not enough time or some obstacle to putting an agreement down in writing.

Jeffrey Cramer, another former federal prosecutor, told TPM that “if there’s not a written agreement here, it wouldn’t matter if Corsi at least told the other defendants that he’s not cooperating, if he’s playing both ends, it’s gonna get messy.”

Corsi added to TPM that his supposed agreement was “one-way,” denying that he is putting on an elaborate performance in the media and through his attorneys to convince Trump to issue him a pardon.

“You and the special counsel are entitled to whatever opinion you want,” Corsi said, upon being asked whether he is angling for a pardon. “I think I’m doing this because of my integrity.”

Gene Rossi, a former federal prosecutor at Carlton Fields law firm, said “there’s no such thing as an informal defense agreement.”

“If it’s an informal defense agreement, then Giuliani is just blowing smoke,” he added. “The attorney for the President of the United States has an informal unwritten defense agreement with Corsi?”

“That’s malpractice.”