The second pivotal factor is the outcome of November’s election. Republicans have throughout the impeachment argued for letting the people decide, insisting that removal would preempt the popular will. If Trump loses, and particularly if senators who voted to acquit lose with him, it could be taken as a higher, popular judgment of condemnation of his behavior — in effect, reinstating the constitutional norm.
Then again, if Trump is reelected, it will be as if the electorate had voiced its support for the acquittal. In that event, it will be hard to dispute the argument that the impeachment clause has been neutered.
The upshot is that this November, the Constitution itself will be on the ballot. Even another razor-thin Trump victory will validate the abominable judgment that the Senate is poised to deliver Wednesday. Then God help us when the next president decides to follow Trump’s corrupt path, because the Constitution won’t be able to.