This post has been updated.

The first two paragraphs of this New York Times story are remarkable enough: Despite Paul Manafort having agreed to cooperate with special counsel Robert S. Mueller III’s Russia investigation, his lawyer, Kevin Downing, continued to brief President Trump’s legal team. That’s a highly unusual setup, and one that is generally frowned upon in legal circles.

The next two paragraphs, though, might take the cake. In them, Trump lawyer Rudolph W. Giuliani practically brags about having pulled one over on Mueller by gleaning key information from the arrangement.

Via Times reporters Michael S. Schmidt, Sharon LaFraniere and Maggie Haberman:

Rudolph W. Giuliani, one of the president’s personal lawyers, acknowledged the arrangement on Tuesday 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 the special counsel’s office.
For example, Mr. Giuliani said, Mr. Manafort’s lawyer Kevin M. 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. The president has long denied knowing about the meeting in advance. “He wants Manafort to incriminate Trump,” Mr. Giuliani declared of Mr. Mueller.

In other words, the Trump team is saying this highly unusual arrangement was used to gain a strategic advantage. It isn’t even pretending these were harmless status updates. Giuliani is gloating about having gamed the legal system.

But could that be legally problematic?

The experts the Times talked to generally agreed this is ethically problematic but not illegal, in and of itself. Once you agree to cooperate with the government, your interests no longer align (and often clash) with other subjects of the investigation, and such “joint defense agreements” are usually instantly voided. That’s what happened when Michael Flynn flipped last year and with Michael Cohen this year. But that’s not the same as saying anyone involved will be punished — especially if they never misrepresented what they were doing.

There is another possible legal consequence, though, and it involves the broader obstruction of justice investigation. Basically, Mueller’s team could decide that this arrangement has amounted to witness tampering or obstruction, or that it adds to a mountain of evidence on that latter count. If the arrangement between Manafort’s lawyer and the Trump legal team is viewed as an effort to impede the investigation by feeding information from sensitive sessions between the Mueller team and Manafort to the Trump legal team — an elaborately conceived plan to tip off Trump — there could be repercussions.

“If the purpose was to gather information about what’s going on in the investigation and share it back with others who are potential subjects of the investigation so that they can take steps to ensure that the investigation does not come to fruition,” former federal prosecutor Barbara McQaude said Tuesday night on MSNBC, “I think that could amount to obstruction of justice.”

Some former federal prosecutors offered similar takes.

As Honig notes, the obstruction question turns on whether there was provable intent. Did the Manafort team reach an agreement with the Trump team to basically inform on the investigation in exchange for something — like, for instance, a pardon? (A federal pardon wouldn’t protect Manafort from potential prosecution under state laws, though.) Was the cooperation agreement just a ruse to get someone on the inside? Was there an explicit quid pro quo?

That’s speculative, but Giuliani’s comments don’t exactly downplay the possibility, nor does the fact that Manafort continued lying to Mueller’s team, according to the special counsel. And why else would Manafort’s legal team even take the risk of running afoul of Mueller after agreeing to cooperate in exchange for leniency? What could possibly be in it for them to keep working with Trump’s legal team?

Mueller may now have reason to probe the contacts between the two legal teams, and those contacts became no longer privileged after Manafort signed his cooperation deal. It would be a legal fight, to be sure, but one in which Mueller would have a plausible chance of success. “Mueller could defeat any claim of privilege for the communications between Dowling and Trump’s lawyers,” said Stephen Gillers, an expert on legal ethics at NYU’s law school. “However, that claim is only likely to be made before the grand jury if Mueller were to subpoena any of those parties to the grand jury.”

And if Trump does wind up pardoning Manafort, this arrangement will be cast in a whole new light. He will be pardoning the man who Trump’s own lawyer said provided strategic information about the inner workings of the Mueller probe. The obstruction plot thickens.