The collapse of the Manafort-Mueller cooperation deal may be less mysterious than it first appeared. There are several reasons why Paul Manafort may have lied to the special counsel’s office, violating the terms of his plea agreement—the desire to protect sources, secrets, family—but one stands out, given the information that has come to light in the last 48 hours: a presidential pardon. “The only way this could make any sense is if he doesn’t believe that he is going to face any consequences at all,” remarked former F.B.I. counter-intelligence agent Asha Rangappa. Indeed, as The New York Times reports, the falling out appears to derive, in part, from Manafort’s highly unusual decision to maintain a legal back channel to attorneys for Donald Trump, even after Manafort decided to cut a deal.

It’s clear how the president may have benefited from the arrangement. As Trump attorney Rudy Giuliani told the Times, Manafort’s lawyer Kevin Downing gave the White House valuable insight into Mueller’s interests, such as the June 2016 Trump Tower meeting where Russians offered dirt on Hillary Clinton. Why Manafort would have agreed to keep the back channel open after taking a plea deal is harder to explain.

“I have never heard of anyone doing this,” Renato Mariotti, a former federal prosecutor, told me, incredulous. Manafort and Trump did enter into a joint defense agreement early on in the Mueller investigation, but under normal circumstances their cooperation would have ended when Manafort flipped, since their interests would no longer be aligned. “All a joint defense agreement is is a way of formalizing that common interest,” Mariotti told me. “How could somebody who has surrendered to the government and is helping the government have the same interest in any way with somebody who is fighting the government? It literally boggles my mind, I don’t understand it.” John Marston, a former Washington, D.C., assistant U.S. attorney, was similarly puzzled. “There really is no such thing as a half-cooperator, or a partially committed cooperator—you are either all in or you end up all out.” When Manafort signed his cooperation agreement with Mueller, he agreed in writing to cooperate against anyone—including the president.

Was Downing talking to Giuliani the final straw that prompted Mueller to dissolve Manafort’s deal? Mueller, after all, accused Manafort of lying about a “variety of subject matters” to investigators in a court filing Monday. “When you signal to prosecutors that you are not committed to solely helping them, such as by giving an inside scoop on the investigation to others who are involved but who do not have your inside access, it certainly can affect the prosecution’s patience and willingness to work through things like perceived false statements,” Marston said.

The only rational explanation for Manafort’s behavior, legal experts say, is that he’s gunning for a pardon. “From a Manafort perspective, the only reason to be doing this is to curry favor with Trump—either for a pardon or for some other benefit, which I don’t know what that would be,” Mariotti told me. Marston echoed the sentiment. “This seems like this is aimed at enhancing pardon consideration,” he said. “But hard to blame Manafort for that—a pardon is a powerful thing, and maybe they’ve decided they have a better chance of getting a pardon than they do a favorable sentence through cooperation. Who knows, maybe they had even decided that going into the cooperation.”

Could conspiring to enter a cooperation agreement with the intention of violating it, all while ferrying information to another target of the same investigation, constitute witness tampering or obstruction of justice? “In this situation, these were lawyer-to-lawyer conversations, so it seems unlikely to me,” Marston said. (In March, the Times reported John Dowd, then Trump’s lawyer, had discussed the possibility of a pardon with Manafort’s attorneys.) Any kind of quid pro quo, however, might be illegal—or, at the very least, impeachable. (President Nixon was impeached, among other things, for “endeavoring to cause” defendants to expect “favored treatment” in exchange for their silence or false testimony.) “If there was some promise of a pardon in exchange for lying to the Mueller team, or any kind of encouragement to impede the Mueller investigation, those things could rise to the level of tampering or obstruction,” Marston added. “But it would be shocking if that actually happened, and even more shocking if there was proof of it.”

Trump has publicly danced right up to that line—whether he has crossed it is a question for Mueller and for Congress. In August, before Manafort pleaded guilty, he praised him in a series of tweets, calling him a “brave man” for refusing to “break.” On Wednesday, Trump sent his former campaign chairman another encouraging signal in an interview with The New York Post. “It was never discussed, but I wouldn’t take it off the table,” he said. “Why would I take it off the table?” In other words, one might argue: stay strong.

As Harry Litman, a former United States attorney and deputy assistant attorney general, told me earlier this year, “If Trump is either dangling a pardon or giving a pardon in order to prevent Manafort from giving truthful testimony to Mueller, that’s obstruction of justice. And it doesn’t change it that he’s the president of the United States. In some ways, it aggravates it.”