As special counsel Robert Mueller prepares for a potential climactic interview with President Trump, his team continues to bore into potential links between Russian intelligence and Trump's former campaign chairman Paul Manafort. In new court documents filed Wednesday, Mueller is asserting the strongest ties yet: that Manafort and his associate Richard Gates communicated with a former Russian spy with ongoing connections to Russian intelligence during the 2016 campaign.

The new information is contained in the prosecution's sentencing memorandum of Alex van der Zwaan, the former Skadden Arps attorney who collaborated with Manafort and Gates on pro-Russian work in 2012. Van der Zwaan pleaded guilty last month of lying to Mueller's investigators about his conversations with Gates and a "Person A," who is widely believed to be Konstantin Kilimnik, a former associate of Manafort.

In recommending that van der Zwaan serve jail time, prosecutors note that his lies about Person A were "material to the Special Counsel's Office's investigation" because "special agents assisting the Special Counsel's Office assess that Person A has ties to Russian intelligence services and had such ties in 2016." Mueller's team has asserted ties between Person A and Russian intelligence in the past, but this assessment marks the first time they have said those ties were ongoing at the time of the campaign. (Kilimnik himself told the Washington Post last June that he has "no relation to the Russian or any other intelligence service.")

In a separate filing, Alex van der Zwaan insists that his lying to investigators was not motivated by a desire to impede Mueller's investigation, but by a fear of his superiors at Skadden Arps discovering he had violated the firm's policies by recording his calls with Person A, Gates, and Skadden partners.

"During the interview, Alex was keenly aware that he was not speaking only to the OSC. Alex was represented by Skadden lawyers, and anything he shared with the OSC would simultaneously be heard by Skadden. In his mind, his boss was listening to every word," the filing reads. "Focused on preserving his career at Skadden, and fearful that truthful answers could lead to discovery of the recordings (an in particular, the discovery that he had recorded a Skadden partner), Alex made a terrible decision: He decided to cut off the inquiry at its inception by lying about the September 2016 conversations with Gates and Person A."

Due largely to the complicating presence of van der Zwaan, it remains far too early to judge how badly this revelation reflects upon the Trump campaign. On the one hand, Mueller is now explicitly asserting that Trump's campaign manager was linked to Russian intelligence during the campaign. On the other, it's a very tenuous link indeed: that Manafort, through Gates, was interacting with van der Zwaan, who was interacting with Person A, who had ties to Russian intelligence. Meanwhile, there's no reason to believe, based on the information available, that these linked conversations had anything to do with the 2016 election at all. Rather, both the prosecutors' and the defendant's accounts indicate that conversations between Gates, van der Zwaan, and Person A were related to Manafort and Gates' continued attempts to cover up their prior alleged illegal activities in connection with their past lobbying in Ukraine.

In other words, these assertions reveal practically nothing at all about the central question of the Russia investigation: whether the Trump campaign collaborated with Russians in their illegal attempts to destabilize U.S. elections. But they do serve as a reminder to observers and subjects of the investigation alike: Robert Mueller still holds all the cards, and it remains unwise to attempt to deceive him.