What are the legal terms at play here? Spoliation and fruit of the poisoned tree?
Seems like Manafort and Flynn won the anti-Mueller lottery.
IIRC, the Rosenstein letter to Mueller did not order him to start a new investigation starting May 17, 2016. He was to continue the already started investigation which was going on well before May 17 and during the period of the missing texts and probably the fisa abuse.
We know, then, that the entire 1st stage of the investigation was corrupt and that this 2nd stage was built on it.
Therefore, the entire investigation is the fruit of the poisoned tree.
