Whatever cards Mueller has to play, he’s not ready to show them.
Manafort is a lock to go down for tax evasion and other financial crimes, so it makes sense for Mueller to stay away from RussiaRussiaRussia.
Mueller has not charged Manafort with tax evasion.
Mueller has charged him with not filling out paperwork from a decade ago when Manafort was working with Clinton and Podesta in the Ukraine.
Podesta never filled out the forms until after Manafort was indicted. Ten years after they were required.