In a line many on the right love to quote, former Defense Secretary Robert Gates accused Joe Biden of being “wrong on nearly every major foreign-policy and national-security issue over the past four decades.” Gates isn’t wrong, though he, too, has been wrong on foreign policy questions, and has anyone who’s made enough tough decisions over that many decades (see Churchill, Winston).What conservatives omit is that Gates dedicates most of the passage to praising Biden’s character: Joe is simply impossible not to like. He’s down to earth, funny, profane, and humorously self-aware of his motormouth. Not too many meetings had...