What is unclear is whether he will cooperate with prosecutors as they investigate Russian interference in the 2016 election, and potential collusion by members of Trump's campaign.
It has been rumored that Trump would grant him a presidential pardon for his crimes.
A guilty plea helps Manafort avoid the possibility of additional prison time in the event that the Washington jury were to have convicted him.
First, Schiff noted, Mueller would likely want to know from Manafort as much as possible about the infamous Trump Tower meeting of June 2016, which Donald Trump Jr., Jared Kushner, and Manafort attended in the full expectation of getting dirt on Hillary Clinton supplied by the Russian government. Previously, he was facing those charges, plus five others, including obstruction of justice, providing false statements, conspiracy to launder money, and acting as an unregistered foreign agent.
Manafort is expected to appear in court later Friday morning. He also cooperated in the government's case against Manafort.
The details of the plea agreement, and whether Manafort would cooperate with prosecutors, were not immediately known.
On Twitter on August 22, Trump wrote: "Unlike Michael Cohen, he refused to "break" - make up stories in order to get a 'deal". He is now accused of conspiracy against the United States and conspiracy to obstruct justice. He had another trial coming up this month, and this plea deal was his way of avoiding it. In that case, he was found guilty on eight counts of bank fraud, tax fraud and failure to report a foreign bank account.More news: 'Historic storm' lashes Carolinas with heavy rain, floods
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The 38-page information document is extraordinary in its scope, and it lays out detailed counter-arguments to Trump's "witch hunt!" tirade, and the cost of the investigation is of no concern now that Manafort's wardrobe full of ostrich jackets could pay for a second Mueller investigation all on their own.
His decision to plead guilty, indicated in a court filing on Friday, came just days before jury selection was set to begin September 17 in Washington, where Mueller accused him of conspiring to launder money, acting as an unregistered foreign agent of Ukraine and obstructing justice.
Manafort's decision could be a blow to Trump, who last month praised his former aide for not entering into an agreement with prosecutors, as the president's former personal lawyer Michael Cohen had.
In February, a USA federal grand jury charged 13 Russian nationals and three Russian companies with plotting to interfere in the 2016 us presidential election.
Manafort will remain in jail for the time being, and has to forfeit four of his homes, as well as other assets. Papadopoulos has since agreed to work with Mueller's investigation.
It's true that nothing public in Mueller's investigation so far has touched Trump on the central questions of collusion with Russian Federation or obstruction of justice.
Kilimnik is charged as a co-defendant in Manafort's DC criminal case, for the witness tampering accusation.