Joe Biden called President Donald Trump “George” on Sunday, as if he were running against George H.W. Bush, George W. Bush, or maybe George Washington, before catching himself. (Or being helped by someone outside the camera’s view.) He appeared to be a tired old man in need of help with his everyday life. Yet at both debates, though he made mistakes, he looked to be far more sentient, at times even sharp, in stark contrast to the doddering senior citizen we usually see. How can this happen? “What kind of country we’re gonna be,” Biden asked in a weekend interview...