After watching this disaster unfold, the bottom line for me is that this "impeachment" was nakedly political from beginning to end.
Whatever else I may or may not know for certain, I do know this: the Founding Fathers never intended for impeachment to be simply because one party didn't like the other party's president. There has to be some kind of crime, period.
And as for quid pro quo, the original "charge", that happens every day of a president's term. ALL politics is a form negotiations in one way or another, and that's what the Democrats accused Trump of doing: negotiating with whatever he had at hand. If Joe Biden thinks this foofaraw is over because he and his son didn't have to testify, he better think again. He hasn't heard the last of this, and I believe it's ultimately going to sink his campaign, if Bernie Sanders doesn't do it first.
"Long is the way and hard that out of Hell leads up to light." -John Milton