Here's my theory on the Paul Manafort prosecution/persecution. It appears the way the corrupt members of the FBI have worked in the past is they look for the weak link tie in to their target. In this case, POTUS is the target. They probably already knew of Rick Gates hidden life and his embezzlement of Manafort's money. How would they know this?? Tony Podesta, of course! So Gates is guilty of crimes that are easily proven. How does Gates get out of his predicament?? Provide testimony against Manafort, whether true or manufactured. Why did Manafort work for free? Was this Gates idea? I don't know.
Even the dossier's outline started with Russians who were compromised and then a meeting was arranged to tie in to POTUS. How do you efficiently and quickly work your way through a maze? Start at the end and work your way back.