We all witnessed some of the most shocking and confounding political events of our lifetime: the careening last stage of Donald J. Trump’s reelection campaign, the president’s audacious election challenge, the harrowing mayhem of January 6, the buffoonery of the second impeachment trial. But what was really going on in the inner sanctum of the White House during these calamitous events? What did the president and his dwindling cadre of loyalists actually believe? And what were they planning?