The story revealed that Special Counsel Robert Mueller claimed Manafort had "lied about sharing polling data. related to the 2016 presidential campaign" with Konstantin Kilimnik, a Russian-Ukrainian businessman who the USA claims to have links to Russian intelligence and was charged previous year with tampering with potential witnesses.
"This shows that Bob Mueller can demonstrate to a court, without the testimony of Paul Manafort, that the campaign had a connection to Russian intelligence and the connection involved information going from the campaign to the Russians", Napolitano said.
Legal experts told ABC News this week that sharing campaign polling data with a foreign person is not a crime, but could be an important piece to the puzzle concerning possible Trump campaign coordination with Russians during the 2016 campaign - a subject being investigated by special counsel Robert Mueller's office.
That information was included in a court filing this week that appeared to inadvertently include details not meant to be made public and indicates a pathway by which the Russians could have had access to Trump campaign data.
Prosecutors alleged that Manafort lied about providing Kilimnik with the polling data. President Trump denies any campaign collusion with Russian Federation. Instead, they said, they would be open to resolving the matter during pre-sentencing reports.
But US prosecutors have since accused Manafort of lying to investigators, complicating his efforts to get a reduced sentence in exchange for his cooperation.
Rudy Giuliani, a lawyer for Trump who has repeatedly criticized the Mueller probe as a fruitless "witch hunt", dismissed the sharing of data with Kilimnik as inconsequential. Manafort pleaded guilty in September to conspiracy charges related to that Ukraine work, and had agreed to cooperate truthfully with Mueller's team.