One day after Special Counsel Robert Mueller said that Paul Manafort had lied and violated his plea agreement with Federal prosecutors, and as a result should be sentenced immediately, the NYT has reported that in a "highly unusual" arrangement, a lawyer for Paul Manafort had repeatedly briefed president Trump's lawyer on what he told Mueller and other federal investigators after he agreed to cooperate with the special counsel.

While the arrangement is not illegal, it reportedly inflamed tensions with the special counsel’s office when prosecutors discovered it after Mr. Manafort began "cooperating" two months ago, with some legal experts speculating that Manafort's backdoor cooperation with Trump's legal team was a bid by Trump's former campaign chair for a presidential pardon even as he worked with Mueller in hopes of a lighter sentence.

Trump lawyer Rudy Giuliani acknowledged the arrangement to the NYT, and "defended it as a source of valuable insights into the special counsel’s inquiry and where it was headed."

Such information could help shape a legal defense strategy, and it also appeared to give Mr. Trump and his legal advisers ammunition in their public relations campaign against Mr. Mueller’s office.

As an example of of what Manafort told the Trump legal team, Giuliani said, Manafort’s lawyer Kevin Downing told him that prosecutors hammered away at whether the president knew about the June 2016 Trump Tower meeting where Russians promised to deliver damaging information on Hillary Clinton to his eldest son, Donald Trump Jr, although this line of investigation is hardly a surprise. Trump has long denied knowing about the meeting in advance, with Giuliani saying that Mueller "wants Manafort to incriminate Trump."

What is notable is that this kind of joint defense agreement is legal, and while Downing’s discussions with the president’s team violated no laws, they helped contribute to a deteriorating relationship between lawyers for Manafort and Mueller’s prosecutors, who on Monday accused Manafort of holding out on them and even lying, despite his pledge to assist them in any matter they deemed relevant. As a result of the collapse of the plea deal, Manafort will now face sentencing on two conspiracy charges and eight counts of financial fraud — crimes that could put him behind bars for at least 10 years.

Just as importantly, Manafort's frequent updates helped reassure Trump’s legal team that Manafort had not implicated the president in any possible wrongdoing, which begs the question just how was Manafort "cooperating" with Mueller for two whole months.

Meanwhile, according to the NYT, Giuliani seized on Downing’s information to unleash lines of attack onto the special counsel.

In asserting that investigators were unnecessarily targeting Trump, Giuliani accused the prosecutor overseeing the Manafort investigation, Andrew Weissmann, of keeping Manafort in solitary confinement simply in the hopes of forcing him to give false testimony about the president.

Meanwhile, in his own repeated Twitter attacks on the special counsel, the president suggested that he himself had inside information about the prosecutors’ lines of inquiry and frustrations. "Wait until it comes out how horribly & viciously they are treating people, ruining lives for them refusing to lie," Trump wrote on Tuesday, and earlier this month tweeted: "The inner workings of the Mueller investigation are a total mess. They have found no collusion and have gone absolutely nuts. They are screaming and shouting at people, horribly threatening them to come up with the answers they want."

As noted above, the basis for Manafort’s legal team keeping Trump’s lawyers abreast of developments in his case is thanks to a joint defense agreement. According to the Times, Trump's team has pursued such pacts as a way to monitor the special counsel’s inquiry. Last month, Giuliani said that the president’s lawyers had agreements with lawyers for 32 witnesses or subjects of Mueller’s 18-month-old investigation, effectively receiving up to date information on virtually every aspect of the Mueller probe.

While joint defense agreements are frequently used by lawyers involved in investigations with multiple witnesses so they can share information without running afoul of attorney-client privilege rules, usually when one defendant decides to cooperate with the government in a plea deal, that defense lawyer typically pulls out rather than antagonize the prosecutors who can influence the client’s sentence. One such example is when a lawyer for Michael T. Flynn withdrew last year from such an agreement with Trump’s lawyers before pleading guilty to a felony offense and agreeing to help the special counsel.

On the other hand, even after Manafort pleaded guilty to two conspiracy counts in September and began answering questions in at least a dozen sessions with the special counsel, Manafort’s lawyers maintained their joint defense agreement with the president’s legal team.

Why would Manafort seek the continuation of such an agreement, even if it meant risking his plea deal? Simple: he wants Trump to pardon him.

Manafort must have wanted to keep a line open to the president in hope of a pardon, said Barbara McQuade, a formder United States attorney who now teaches law at University of Michigan. “I’m not able to think of another reason,” she said. If Mr. Manafort wanted to stay on the prosecutors’ good side, “it would make no sense for him to continue to share information with other subjects of the investigation,” said Chuck Rosenberg, a former United States attorney and senior F.B.I. official. He added: “He is either all in or all out with respect to cooperation. Typically, there is no middle ground.”

Whether Manafort gets a pardon, remains to be seen. Last year, a former Trump lawyer allegedly broached the idea of presidential pardons to lawyers for both Manafort and Flynn as prosecutors were building cases against both men, according to people familiar with the conversations. The lawyer, John Dowd, who later resigned from the president’s team, denied ever raising the prospect of a pardon.

However, to keep Manafort's hopes alive, after Dowd's departure Giuliani himself suggested that Manafort and others might be eligible for pardons after Mueller’s inquiry ends, and the prospect has continued to hover over Manafort’s case. On Tuesday, Sarah Huckabee Sanders, the White House press secretary, said she had no knowledge of any conversations about a pardon for Mr. Manafort. A week ago, after months of negotiations, Trump provided written answers to some questions from Mueller.

That said, even if Manafort lucks out and gets out of prison early, he will be a poor man. The reason is that prosecutors deliberately fashioned Manafort’s plea agreement to counter a possible pardon. As the NYT reports, in forcing Manafort to forfeit almost all of his wealth — including five homes, various bank accounts and an insurance policy — prosecutors specified that they could seize his assets under civil procedures “without regard to the status of his criminal conviction.”

According to UCSD law professor Harry Litman, similar provisions had been used in other such cases, but other legal experts said it seemed tailor-made to ensure Manafort would lose virtually all of his wealth, no matter what Mr. Trump did.

And while Trump will likely end up pardoning Manafort before the president leaves office, whether Trump will also personally fund his former campaign chair's retirement account is an entirely different matter.