Special counsel Robert Mueller’s plea deal with Paul Manafort took unusual steps to undercut President Trump’s ability to pardon his one-time campaign chairman, a report said Tuesday.

The deal contains language that appears intended to discourage Manafort from seeking a pardon and to limit the impact of a pardon if Trump were to grant one, Politico reported, citing a former Justice Department official who served in the administrations of Presidents Ronald Reagan and George W. Bush and other sources.

“What is most concerning to me is that Mr. Mueller, who is a part of the executive branch and is supposed to follow all of DOJ’s policies and procedures, is specifically seeking to impede the ability of the president to exercise his constitutional pardon authority,” the former GOP official, David Rivkin, told the website.

“These waivers are troubling because they have to do with future events we can’t predict,” University of St. Thomas law professor Mark Osler said about provisions in the deal. “They did a pretty good job hiding what they did, but as part of these agreements, sometimes the most important things you want to bury it a little.”

The 17-page deal doesn’t stop Manafort from seeking a pardon, but some lawyers said it appears that Manafort had to promise not to seek another form of presidential clemency that could allow him to keep property worth tens of millions of dollars instead of forfeiting it to the feds, as the plea bargain calls for.

But other lawyers told Politico they didn’t think the language in the agreement was much different than what the Justice Department has done in other cases where defendants are asked to waive rights.

“It always feels like if they’re not overreaching, they’re heavy-handed, but it’s to my sense standard-issue heavy-handed,” said Ohio State University law professor Doug Berman.

Federal Judge Amy Berman Jackson on Friday accepted Manafort’s guilty plea to two felony conspiracy counts. Under the agreement, he faces about 10 years in a federal pen.