On February 29, 2016, Paul Manafort contacted Donald Trump, sending a letter that included a pitch for Manafort’s services with the Trump campaign. In the letter, Manafort touted his work in Ukraine, and discussed working with the rich and powerful, including oligarchs and dictators in Russia, Ukraine, the Philippines, and Pakistan. The letter falsely stated, “I have had no client relationships dealing with Washington since around 2005. I have avoided the political establishment in Washington since 2005.” Manafort further stated he would not seek any pay for the job. Source
On March 28, 2016, Donald Trump publicly confirmed he had hired Paul Manafort to lead campaign efforts relating to delegates. Source By this time, the FBI surveillance on Manafort that had started in 2014 had stopped. Source
When he joined the campaign, Manafort failed to disclose his prior work as a foreign agent, as required under US federal law. Source At the time, Manafort was in debt to Oleg Deripaska by as much as $17 million, in connection to his activities in Ukraine. Source
On June 9, 2016, Manafort was among those in attendance at a meeting at Trump Tower, arranged so that the Russian government could provide allegedly incriminating intelligence on Hillary Clinton as part of the Kremlin’s effort to assist the Trump campaign. Source Manafort’s notes from the meeting, obtained later under a FISA warrant, mentioned political contributions, and the RNC. Source
On June 20, 2016, Donald Trump fired campaign manager Corey Lewandowski and promoted Paul Manafort to the position. Source
A large cache of Manafort’s emails was obtained as part of the Mueller probe into the Trump-Russia conspiracy. These emails included correspondence between Manafort and Konstantin Kilimnik, a Ukrainian employee of his consulting practice who once served in the Russian army. Kilimnik was suspected of having ties to Russian intelligence and was a person of interest in the Senate Intelligence Committee investigation into Trump–Russia collusion. Source In one email from Manafort to Klimnik dated July 7, 2016, Manafort offered to provide private briefings on the US presidential race to Oleg Deripaska, a Russian oligarch with close ties to the Kremlin. It is not known whether the briefing took place. In the emails, Manafort also expressed his desire to use his new notoriety from his new position as Trump’s campaign manager to collect past debts. These and other emails between Manafort and Kilimnik were written using veiled language and what appeared to be code words. Source
On August 14, 2016, the first published story appeared about Paul Manafort’s illegal kickbacks from the pro-Russian Ukrainian political party, Party of Regions. Source
On August 19, 2016, following blowback from news reports about Manafort’s dealings in Ukraine, Paul Manafort officially resigned from his position as campaign manager for the Trump campaign. Source
In June 2017, Manafort was forced to update his official filings to admit receipt of $17.1 million for his work with the Party of Regions, and retroactively registered under the Foreign Agents Registration Act (FARA). Source Nevertheless, FARA violations based on his activities in Ukraine were among the charges for which both Manafort and Gates were indicted on October 30, 2017. Source
Note that when Manafort joined the Trump campaign he had $17 million in debt to pro-Russia interests, which is the same amount he admitted in 2017 to have received in payments from the Party of Regions. It’s not clear but it appears Manafort may have utilized his position in the Trump campaign to persuade pro-Russian parties to pay off his debts to Oleg Deripaska, causing Deripaska to drop his lawsuit against Manafort.
Manafort’s expressed desire to leverage his position in the Trump campaign to be made “whole” by collecting past debts from Russian oligarchs appears to have created a conflict of interest in his position as campaign manager.