Impeachment is, ultimately, a political act.
Congress can impeach and convict for any reason they damn well please.
As long as they are willing to suffer the electoral consequences.
And, of course, the asymmetrical and non-political responses of the electorate.
As a 98er, you'll remember that the response of the democrats and their Media was embarrassment over Big Bill's dick-out, and scrambling to contain the fallout from the clear felonies he committed.
We're not going to be burdened by that stuff - nor are we going to pay any attention to the lying Media, just like we didn't in October/November 2016.
"asymmetrical" - with symmetrical objects, indeed...