Trump and the Republicans could shut it right down by just not showing up. I wonder if Trump is not looking forward to presenting his fraud evidence to the public where thee msm has to cover it. ;-{>8
A senate quorum is a majority, or 51. The problem is that they don't count who's there unless someone requests it. That means that business will continue unless there's 1 republican there to request a count. Since he's there, he's counted too. If all 50 Dems are there, plus the Rep, that's a quorum and the trial goes on.
