No upside

      Democrats have desperately chasing the witness car at the tRump impeachment trial and they may have finally caught it, hopefully not to their dismay.
       The trial has so far gone according to plan.  Both sides have energized their bases with tales of the other side's perfidy and despite a mountain of evidence clearly showing the president's* guilt, he is on the verge of acquittal.  This was never in doubt, despite the outrage of the House managers and Senate democrats.   Now comes the John Bolton surprise and it fuels more outrage.
       If I was Moscow Mitch, I would allow four republicans to join democrats calling for a witness.  Bolton's book is going to come out anyway, so McConnell's reasoning goes, so let's limit the evidentiary part of the trial to a single witness.  Bolton will confirm the charges and not a single republican will defect anyway.   Now they can all say the trial was fair and quite a few moderate dems and independents will agree.  Instead of a sham trial that will keep their partisans engaged until election day, many will despair and drop out.   Meanwhile, tRump supporters will still be outraged at this witch hunt and will probably even re-elect Susan Collins.  I know this is a cynical view of the likely outcome, but I hope McConnell has his 51 votes so the trial has a quick, unhappy ending.