At a plea hearing in a D.C. federal court today, Manafort pleaded guilty to a charge of conspiracy against the United States and a charge of conspiracy to obstruct justice. Manafort, President Donald Trump's former campaign chairman, was convicted in August of eight charges of tax evasion and bank fraud for concealing the money he had made from pro-Russian interests in Ukraine (including its former President Viktor Yanukovych). But those were only some of the charges against him. He faced an additional trial this month for failing to register as a foreign agent, lying to the feds about it, laundering money, and then attempting to contact and influence the testimony of two witnesses (which, once discovered, resulted in his bail being revoked).
Manafort has agreed in his plea to cooperate with the federal probe to determine the extent that Russian government interests attempted to influence and alter the outcome of the 2016 election. While it's not entirely clear what that will mean as yet, that's the part that matters in the long run. The crimes Manafort has been convicted of are not directly connected to Trump and his campaign in any way and most of them preceded Manafort's work for Trump. The response from Trump and the White House has been (and continues to be) that none of these charges show any sort of collusion between Trump and Russia, and that's absolutely true.
But given Manafort's pre-existing financial connections to Russia, his agreement to help prosecutors with further investigations will most certainly feed speculation and theories that there's more to these relationships than we're currently publicly aware of, beyond what we've been told about Russian lobbyists offering stolen emails and data from Hillary Clinton's campaign to Trump's team.
This does not necessarily mean that Manafort has any dirt on Trump, not that this is going to stop any sort of speculation that he does. In a Twitter thread, former federal prosecutor and CNN legal analyst Renato Mariotti explains that Manafort has agreed to cooperate with the feds on any potential activity by anybody that's relevant to Mueller's investigation. That Mueller accepted the plea deal means they believe he certainly must have helpful information about somebody's illegal behavior, but this should not be taken to mean that it's about Trump.
A good indicator as to whether Manafort does have anything about Trump may be to keep an eye on what our unpredictable, uncontrollable president might tweet about his decision to cop a plea in exchange for cooperation. Remember Trump has a very dim view on people who "flip" on him and thinks it should "almost" be illegal.
Manafort has not yet been sentenced for his first round of convictions. Given his age, 69, and the number of charges, he faces the possibility of spending the rest of his life in prison, depending on how harshly the judge decides to punish him.
UPDATE: The details of the plea agreement are starting to be released. The cooperation component appears very extensive. (Here's a link to the full plea agreement)
NEW: Manafort's agreement with DOJ requires him to "cooperate fully, truthfully, completely, and forthrightly," including participating in debriefings, providing all relevant documents, and testifying if the government asks him to. pic.twitter.com/3jGe0Bk1mt— Brad Heath (@bradheath) September 14, 2018