On the issue of the widening and constriction of our sovereign borders, the propulsive fuel for populists far and wide, the virus is a global crisis, though infection rates and governmental responses differ widely. US President Donald Trump’s cry of “America First” and Boris Johnson’s “take back control” Brexit had winning voter appeal. Writing in the Financial Times last week, Philip Stephens commented archly: “Viruses do not respect state frontiers. The worldwide spread of coronavirus has instead given eloquent expression to the stubborn fact of international interdependence.” But quarantines, travel bans, tourism declines and border closures mean a huge global separation as well...