Since his investigation into Russian election interference began 18 months ago , the special counsel, Robert Mueller, has had very little to say. Mr. Mueller, in fact, has let court filings and appearances by his team of lawyers do all of the talking, at least publicly, as the law and facts have led to more indictments, convictions, sentences and rulings — mostly in his favor.

Friday, however, could bring Mr. Mueller’s richest revelation yet. A federal judge has ordered Paul Manafort, President Trump’s former campaign chairman, and prosecutors to her courtroom that day to learn more about the extent of his “crimes and lies” in the course of cooperating with the special counsel, who has accused Mr. Manafort of breaching his plea agreement with the government. (Mr. Manafort informed the court Wednesday that he would not appear on Friday, but instead his interests will be represented by counsel.)

Mr. Manafort, ironically, brought this latest round of troubles on himself. Mr. Mueller’s team has notified the judge that the president’s former adviser lied to the F.B.I. and special counsel lawyers “on a variety of subject matters,” adding that there’s no reason to delay his sentencing any longer. And yet it’s hard not to wonder whether this development was part of a brilliant strategy by Mr. Mueller all along — and what bigger consequences Mr. Manafort’s gambit may still yield.

Then again, it’s already been a banner week for skulduggery on the part of those Mr. Mueller is investigating. The games began over the weekend, when a federal judge rejected the last-ditch effort by George Papadopoulos, a Trump campaign adviser, to avoid serving his 14-day prison sentence for lying to investigators.