I think that Manafort’s close and longstanding ties to the Kremlin may well become part of Mueller’s case in establishing that there was A. a Russian conspiracy, and B. Trump officials were at least aware of it, and maybe participating.
Clearly A is pretty well proven already. No one disputes there was “meddling” directed by the Russian state.
Mueller is trying to get B via these various plea deals. That still doesn’t necessarily touch Trump, though he did “joke” that the Russians should look for Hillary’s missing emails, and he did draft the lie about Don Jr’s meeting in Trump tower with Kremlin operatives.
Your talking pure BS. A Russian conspiracy? Where and how? And please don’t tell me about the troll farm.