Paul Manafort, President Donald Trump's former campaign chairman, leaves the Federal District Court after a hearing in Washington, May 23, 2018. Credit: Jose Luis Magana | AP

New revelations about Paul Manafort’s interactions with a Russian associate while he was leading President Donald Trump’s campaign provide a window into how extensively the special counsel has mapped interactions between Trump associates and Russians in his 20-month investigation.

When Manafort pleaded guilty in September to federal crimes related to his work advising Ukrainian politicians, Trump said the admissions by his former campaign chairman had “nothing to do” with the special counsel’s main mission, which Trump described as “looking for Russians involved in our campaign.”

But new details inadvertently revealed in a court filing last week — including the fact that Manafort shared polling data about the 2016 race with an associate who allegedly has ties to Russian intelligence — indicate that special counsel Robert Mueller has also been scrutinizing interactions between Russians and Manafort while he helmed Trump’s presidential bid.

Manafort is among at least 14 Trump associates who interacted with Russians during the campaign and transition, according to public records and interviews.

[Manafort shared 2016 polling data with Russian employee, according to court filing]

The new examples of Manafort’s communications serve as a reminder that much about Mueller’s findings remains unknown in what are widely believed to be the closing weeks of his probe.

Advisers to Trump are bracing for a final report by the special counsel, a confidential document summarizing his findings that they believe could be turned over to senior Justice Department officials next month.

What Mueller will conclude — and even the full scope of his investigation — remains closely held by the special counsel.

Mueller’s appointment was precipitated by Trump’s firing of FBI Director James Comey in May 2017 — a move that also led the FBI to open an investigation into the president to determine whether he obstructed justice and whether he sought to aid Russia, according to people familiar with the matter who spoke on the condition of anonymity. That investigation, which has both a criminal and counterintelligence component, was continued by Mueller.

The new information about Manafort indicates that Mueller has been exploring what he may have communicated to Russians while working for Trump. And it serves as a stark reminder that as Trump was offering Russia-friendly rhetoric on the campaign trail, his White House bid was led for a time by a man with long-standing ties to powerful Russian figures.

Manafort, an international lobbyist and political strategist, was embroiled in a multimillion-dollar financial dispute with Russian businessman Oleg Deripaska, who is close to President Vladimir Putin, according to court filings. He was also owed money by a political party in Ukraine that had failed to pay him for work he did after his client, the ousted leader Viktor Yanukovych, fled to Moscow amid public protests in 2014, filings show.

[Mueller says Manafort told ‘discernible lies,’ including about contacts with employee alleged to have Russian intelligence ties]

Even as he was working for the Trump campaign, Manafort continued to communicate with Konstantin Kilimnik, a Russian employee of his consulting business who the FBI says was linked to Russian intelligence, prosecutors said in court papers last year.

A talented translator with impressive language skills, Kilimnik had been trained at a Moscow university known as a recruiting ground for the Russian intelligence services. After a stint in the military and time spent working for the International Republican Institute in Moscow, he was hired by Manafort in 2005 to assist his political consulting business in navigating the complicated Ukrainian political scene. Friends said Kilimnik emerged as Manafort’s right-hand man in Kiev and Russia, including serving as Manafort’s liaison to Deripaska.

In a written statement to The Washington Post in 2017, Kilimnik denied that he had connections to Russian intelligence. But in documents filed in court last year, Mueller’s prosecutors wrote that Manafort’s deputy, Rick Gates, had said Kilimnik told him that he had formerly been an officer in the GRU, the Russian military intelligence unit accused of engineering the 2016 election interference. Prosecutors said the FBI has assessed that Kilimnik’s intelligence ties continued into that year.

New details about what Manafort and Kilimnik discussed during the campaign emerged last week, when Manafort’s team sought to rebut the allegation by the special counsel that Manafort lied to investigators after he pleaded guilty last fall and agreed to cooperate.

They argued that Manafort, who has been jailed since June and who they said suffers from gout and depression, simply failed to remember certain key details until prosecutors refreshed his memory with documents and other evidence. In previous court filings, they have contended that Mueller has never turned over evidence to show that Manafort was in contact with Russian government or intelligence officials, suggesting that prosecutors have not detailed their evidence against Kilimnik.

Still, in sections of a court filing that they had intended to be sealed from public view, Manafort’s lawyers did not contest new details that Mueller’s team apparently accused Manafort of lying about: that he shared polling data related to the presidential election with Kilimnik and discussed with him a possible peace plan for Ukraine.

In their filing, Manafort’s attorneys said he did not recall either topic, because he was busy with his campaign duties.

A spokesman for Manafort declined to comment.

[FBI probed possibility that Trump sought to aid Russia]

A judge has ordered Mueller’s team to file on Monday a new document explaining the “factual and evidentiary basis” to believe that Manafort lied in his interviews. The document will likely lay out in more detail what evidence Mueller has gathered about Manafort’s communications with Kilimnik. However, that information may be redacted from public view.

The limited information revealed about their interactions suggests that the Russians may have seen Manafort as a politically connected figure who could help promote their interests, according to experts on the region.

The U.S. had imposed punishing sanctions on Russia after it invaded Crimea in 2014. Anders Aslund, an economist and senior fellow at the Atlantic Council who has studied Russia and Ukraine, said a top Russian priority was a solution for Ukraine that recognized Russian control of Crimea and lifted sanctions.

Any assurance Manafort might have offered that a Trump administration would accept such terms would have created a powerful incentive for Russia to root for a Trump victory – and to work to secure that outcome.

“It’s clear that Moscow hoped Trump would win,” said John Herbst, a former ambassador to Ukraine, who served in top State Department posts under Democratic and Republican administrations. “And then Moscow hoped the new administration would pursue a weaker policy, meaning weakening existing sanctions against Russia and not treating Russian aggression in Ukraine as an obstacle to better relations with Washington.”

After Trump’s inauguration, a Ukrainian peace plan considered friendly to Moscow’s interests was delivered to Trump’s personal lawyer Michael Cohen by a Ukrainian lawmaker.

“The point here is that all roads go to the Kremlin,” Aslund said.

[New report on Russian disinformation, prepared for the Senate, shows the operation’s scale and sweep]

The terms of the Ukraine plan that Kilimnik and Manafort discussed in 2016 are unknown.

But in an interview with Radio Free Europe/Radio Liberty in February 2017, Kilimnik said he was championing a proposal in which a new leader would take power of a contested Ukrainian region who had not participated in recent bloodshed there. Kilimnik proposed Yanukovych, who at that time was living in exile in Moscow and was reviled by many Ukrainians.

Manafort’s spokesman has said Kilimnik and Manafort met in Madrid in January or February of that year, another topic about which Mueller’s team said Manafort had lied.

In the February 2017 interview, however, the Russian said Manafort had played no role in formulating his so-called “Kilimnik Plan.”

For Manafort, a Russia-friendly Ukrainian peace plan could have had personal benefits, paving the way for the return of Yanukovych, for whom he had worked from 2005 until the Ukrainian was ousted in 2014.

By the time he joined Trump’s campaign in March 2016 to lead the candidate’s convention strategy, his consulting firm had collected more than $60 million from clients in Ukraine, but he was still deeply in debt to Deripaska and others, according to court documents and testimony.

Still, when asked on NBC’s “Meet the Press” on April 10, 2016, whether he would cease work for controversial clients while working for Trump, Manafort responded, “I’m not working for any clients right now other than Mr. Trump.”

[Roger Stone says he had ‘no contact’ with WikiLeaks’ Julian Assange]

The next day, Manafort emailed Kilimnik to scheme how to use his Trump role as a path to recovering his financial equilibrium. In documents turned over to Congress and Mueller and previously described to The Post, Manafort and Kilimnik exchanged gleeful emails about the positive press Manafort was receiving because of his new Trump role. In one, Manafort wrote to ask whether the “OVD operation” had seen the articles, an apparent reference to Deripaska, adding, “How do we use to get whole?”

Kilimnik told The Post in 2017 that he came to the United States to meet with Manafort on May 7, 2016, and communicated with him frequently as Manafort’s role in Trump’s campaign expanded.

“We talked about bills unpaid by our clients, about (the) overall situation in Ukraine where we spent 10 years working together, and about the current news, mostly related to the perception of the US presidential campaign in Ukraine,” Kilimnik said then in a statement.

By July, Manafort had been named Trump’s campaign chairman, replacing manager Corey Lewandowski, and Trump had sewn up the Republican nomination.

Foreign policy experts wary of Russia grew increasingly concerned with Trump’s campaign rhetoric.

[Mueller’s team investigating candidate Trump’s late-night calls to mentor Roger Stone]

Trump had praised Putin several times on the campaign trail. In July, he began more stridently questioning the United States’ commitment to NATO.

When WikiLeaks published thousands of stolen Democratic Party emails on July 22, Trump appeared to be unconcerned by the possibility that Russian operatives may have been behind the hack. “Russia, if you’re listening, I hope you’re able to find the 30,000 emails that are missing,” he said at a news conference of personal emails Hillary Clinton had deleted while secretary of state.

Throughout this time, Manafort remained in contact with Kilimnik.

On July 7, Manafort wrote Kilimnik that if Deripaska required “private briefings” about the Trump campaign, “we can accommodate,” according to emails read to The Post by people familiar with the discussions. They spoke on the condition of anonymity to discuss matters under investigation.

A spokeswoman for Deripaska has said the Russian businessman was never offered nor received briefings about the American campaign.

Then, on July 29, Kilimnik emailed Manafort and cryptically told his boss that he had met that day with the man who had given Manafort the biggest jar of “black caviar” several years earlier, an apparent reference to money. Kilimnik said the man had messages to pass along to the Trump campaign chairman. Kilimnik suggested that he come to the U.S. for a meeting.

Kilimnik has told The Post that he and Manafort met at the Grand Havana Room in New York on Aug. 2. But he insisted that his in-person meetings with Manafort were “private visits.”

“They were in no way related to politics or [the] presidential campaign in the U.S.,” he wrote.

[Author gave Trump adviser advance notice of WikiLeaks plan to leak Clinton emails, filing says]

He said the two men discussed unpaid bills and the situation in Ukraine. It is not clear what else they might have talked about.

But the court document filed last week showed that Mueller has gathered evidence that Manafort and Kilimnik had discussed a peace plan for Ukraine “on more than one occasion,” including during the campaign, when Manafort’s attention was focused elsewhere, his lawyers said.

Days after the two men met in New York, Manafort was forced to contend with damaging news stories about his work in Ukraine. He resigned from the campaign Aug. 19.

Washington Post writer Devlin Barrett contributed to this report.