Meanwhile, our old friend Byron York had a fascinating report on Kurt Volker’s deposition. Volker pushed back strongly against Adam Schiff’s insistence that the Ukrainians felt pressured over the the withheld funding. If Volker is right, it raises the possibly that Trump wanted to use the suspended aid as leverage, but it didn’t happen for whatever reason (bipartisan support for releasing the funds, push-back from the professional diplomats, and perhaps legal concerns, which Mulvaney mentioned yesterday).

If this is all correct (and I’m admittedly speculating), a truthful and sound defense would give ground on the impropriety of the focus on the Bidens, but emphasize that nothing came from any pressure campaign, which was quickly abandoned. Since Trump only very rarely admits any error, he is loath to do this.

Meanwhile, the black box of the controversy is Rudy Giuliani and his political machinations and business dealings in Ukraine. This is where there’s the most potential for truly explosive revelations, and where the White House has to be very nervous.