I'll be brief, and to the point:
Two reasons Trump MUST be impeached:
1: To prevent him from issuing a blanket pardon to the folks who sacked the Capitol. If he did so, it would guarantee conviction, so impeachment may serve as a deterrent;
a. Congress needs to prevent those pardons for its own protection from future despots. Those who engaged in this act of insurrection must be brought to justice as a deterrent.
b. Forces him to abandon his own supporters which they will see as a betrayal.
2. To prevent him from running again. Which is also why the imminent end of his term does NOT make the matter moot. (Which just might look attractive to folks like the feckless Cruz who may be searching for some act of redemption for the rank and file after their debacle of challenging votes.)
