A man carries a bag on his head as he travels from Russia across the border to Georgia at the Zemo Larsi/Verkhny Lars station, Georgia, Sept. 26.IRAKLI GEDENIDZE/Reuters Ian Buruma is the author of The Churchill Complex: The Curse of Being Special, From Winston and FDR to Trump and Brexit. It is not exactly clear how many Russians have left their country since the beginning of the war on Ukraine. Some say more than a million, some say less. But sheer numbers may be less important than the calibre of many leavers. They are among the most highly educated Russians:...