I think that one of the most uncovered and lethal parts of this whole Russia mess is that they will find a number of elected officials in bed with the Russians. They will all be Republicans and there will be way more of them then anyone would think.
When people do things like the Republicans running interference for Trump when they are fully aware he is conspiring with Russians then there is a piece of the puzzle missing. Mitch and the rest of the Republican leadership is under Putins thumb.
How, why and how much? that is the mystery that has yet to be uncovered.