Manafort had long resisted the idea of cooperating even as prosecutors stacked additional charges against him in Washington and Virginia.
According to the presiding judge, such co-operation includes sitting for interviews and briefings with Robert Mueller's team, handing over any relevant documents, and testifying before any future grand juries or, if necessary, criminal trials. In addition to the financial and lobbying charges against Manafort, the special counsel's team has said it's investigating allegations he colluded with Russian Federation while working for Trump.
Here's how it all shakes out.
Former Trump campaign chairman Paul ManafortPaul John ManafortManafort reaches "tentative" plea deal with Mueller: report Giuliani says possible Manafort plea deal not a concern Manafort seeks plea deal without special counsel cooperation: report MORE agreed to forfeit his apartment in Trump Tower instead of one his bank accounts in his plea deal with special counsel Robert MuellerRobert Swan MuellerSasse: US should applaud choice of Mueller to lead Russian Federation probe MORE.
The second count explains how, between February and April of this year, Manafort conspired to obstruct justice through witness tampering. This would suggest that Trump truly means what he says: Manafort was a bit player who has nothing of significance to convey to Mueller. Mueller has collected folders upon folders of information since he began his investigation and spoken with dozens of witnesses. It was the first time his lawyers had to present evidence in a courtroom and convince a jury of their case. "It potentially opens up lots of doors that probably haven't been opened before".
Some legal experts said that if Trump and his advisers knowingly solicited help from Russian Federation, they may have violated campaign finance laws, and a statute that criminalises conspiracies to impair the functioning of the US government.
The plea deal allows Manafort to avoid a second trial scheduled to begin next week in Washington. The network cited three unidentified sources with knowledge of the deal.
Several media outlets reported that Manafort is close to a plea deal with federal prosecutors.
Now Manafort is taking exactly such a deal.
What's extraordinary about this plea agreement, though, is the lack of protections Manafort has if that scenario were to play out. Despite word that his lawyers were negotiating with the special counsel's office, there was no indication that any kind of co-operative agreement was on the table.
Rudy Giuliani, the former New York City mayor who is representing Trump in the Russian Federation probe, told Reuters on Friday that Manafort "knows nothing harmful to the president and the plea is the best evidence of that".
Amazon's Bezos says Trump should be 'glad' of media scrutiny
These terms of endearment are all things Trump has said about the news media, most of which came out via his Twitter account. Discussing the preschools he would be funding, Bezos said he would focus on children the way Amazon does its customers.
"Manafort's guilty plea - with cooperation! - is an absolute nightmare for Trump, and his family", former federal prosecutor Elizabeth de la Vega told the Guardian in an email.
The scope of co-operative plea deals are usually vague, and this one is no different.
No matter how you look at it, this deal has to be seen as a massive victory for Mueller and his special counsel team. But last month, Trump expressed sympathy for him. There are, however, obvious questions that come to mind - and they point to the heart of the Trump operation.
Manafort took cryptic notes about that meeting, including worlds like "Illici" and phrases like "Offshore - Cyprus" and "Active sponsors of RNC".
Manafort was going to prison one way or another. He was convicted last month of eight financial crimes in a separate trial in Virginia.
Or Mueller may be directly interested in what Manafort, who led the Trump campaign from April through August 2016, can describe about the campaign's interactions with Russians. At age 69, anything longer than the 10-year term he negotiated starts looking like a de facto life sentence.
"Mr. Manafort engaged in a variety of criminal schemes". The once high-flying worldwide political player has been brought crashing down to earth.
Writing in the Atlantic, Franklin Foer, who has dived deeply into Manafort's past career , says that he never put much stock in the rumors swirling around the June 9, 2016, Trump Tower meeting with Russian lawyer Natalia Veselnitskaya, but that Manafort may be able to shed light on the shadowy activities of figures such as Roger Stone: "Manafort's friendship with Stone traces back to the 1970s, when Manafort managed Stone's campaign to run the Young Republicans group".
Manafort is expected to appear in court later Friday morning.