The key point of it seems to be that proving the $130,000 payoff will also prove that Trump interfered with the election all by himself -- with or without the Russians -- in trying to suppress the scandal and keep the information from the electorate. Or there may be a campaign-finance hook in the trail. Either way, with proof of obstruction (which already seems substantial) -- all of these things will be solid grounds for impeachment.
I still think he's guilty of misprision of a felony, or a variant of it called misprision of treason. If you knew the crime was being committed in advance, it's a felony if you fail to report it. And Trump didn't report anything. He just said "Russia! If your listening! Please hack Hillary's e-mails!"
All they need to do is establish a timeline, connecting all the other Trump campaign operatives, hopefully to Trump.
The base will always say Mueller and the Dems are just trying to "fabricate" Trump's crimes. They seem to think that facts themselves are just "made up," and their man is being "framed."
The way they want it to work seems to assume that if you're in power, you get to define the facts, define the crimes, suppress the charges, and railroad your opposition.
[What this country has come to . . . . is this about the state of public education? Some seem to think so . . .an Age of Ignorance . . ]