This is a dramatic, 11th-hour inflection point for the trial, with an eyewitness rebuttal to Trump’s claim that he never tied the hold-up of Ukrainian aid to investigations into Joe Biden.

GOP sources say the revelation could be enough to sway the four Republican senators needed for witnesses — especially since Sens. Mitt Romney of Utah and Susan Collins of Maine have already strongly signaled they’d vote for witnesses…

The intrigue: Bolton submitted the book to the White House on Dec. 30 for a standard prepublication security review for classified information.

The Times notes: “The submission … may have given Mr. Trump’s aides and lawyers direct insight into what Mr. Bolton would say if he were called to testify.”