Schumer made an agreement with McConnell on how this trial would go, and I would presume no witnesses would be allowed cuz the Dems didn't believe they had a shot at a conviction and so they want to get it over with and move on to Biden's agenda (orders from Far Left). So, if Leahy allows one or more witnesses then that breaks the deal and from here on out it's total war, and the GOP can tell the world every day that the Dems can't be trusted. Plus, if the Dems get to call a witness then the GOP gets to call witnesses too and then the case drags on and distracts from the other business. I'd call that a win for the Repubs and a self-inflicted wound by the Dems that can only get worse for them if they continue this nonsense.