As experienced legal guys have noted, Mueller is tightening in concentric circles, like rolling up a Mob operation: little fish like Papadop, Russians outside the US, and now ppl who had contact with Wikileaks.
/1
I think all of those steps have been proven at this point except that last one. That's the last step. /2
Collusion with the campaign? Obvious. Broken laws? Yep.
Impeachable? That's a political decision. /3x