the real danger here is that McConnell will give Schumer what he asks for – agree to have the Senate subpoena witnesses and documents at the start of the trial.
and then what happens? The subjects of the subpoenas all pull a Kupperman, and go to court for a decision on whether they have to testify, or whether they have to obey Trump’s directives.
At which point, McConnell throws up his hands and says “when the House was faced with this kind of situation, it chose not to delay its proceedings, and withdrew its subpoena for Mr Kupperman. For the same reason – avoiding a delay in our proceedings – the Senate will follow the precedent established by the House, and withdraw its subpoenas”
And McConnell will get away with it, because the American people will accept his explanation, because what’s good for the goose is good for the gander…