He may be guilty on the charges, but I don’t know why the entire prosecution isn’t fruit of the poisenous tree, except Manafort’s lawyers didn’t make that argument or demand discovery of the hoax by which Mueller was appointed.
Fruit of the Poisonous Tree is an extension of the Exclusionary Rule. You don’t just call it like a Mulligan in golf. There has to be a “Suppressions Motion and subsequent Hearing. The judge then decides which evidence is allowed or denied. Since there was no Motion or Hearing then any evidence can be used. A Defense Lawyer does not call “Fruit of the Poisonous Tree” and the evidence disappears.
That is why the Meuller Cabal won’t try Flynn. He can still ask for his hearings on evidence he was unaware of as of his plea. Meuller is $hitting his pants over that. Manafort made no such Motions. There are many things that would apply to the meuller SC cases. This is not one of them. Unless Meuller presents evidence that touches upon the illegal search and seizure rules, Manafort is out of luck.
There are a few Motions to Dismiss and Motions to suppress in the docket of this case, as well as the one in DC. One of the motions was roughly that this case is outside of Mueller's jurisdiction.
See Judge Ellis Memorandum Opinion of 26 June 2018, in case 1:18-cr-00083-TSE, E.D.Va.