Ace describes the problem now for anti-Trump partisans -now that there's a special counsel, what happens if Trump did nothing illegal?
They also use the very vague word "collusion" to mask the fact they have no idea what Trump and Putin "colluded" about, or how. What quid pro quo are they alleging? How was this contract formed? Who negotiated this contract?
They have no idea, because they don't even really believe such a thing happened.
If they really believed such things happened, they would specifically say "Trump Aide X, with Trump's knowledge and permission, negotiated to trade American policy Y to Russia in exchange for Russian act Z."