The world is blessed with a brilliant and industrious UN secretary-general, and it was certainly worth tuning in last week to watch António Guterres deliver his New Year message to the planet. As season’s greetings go, it was not exactly festive.

Intercut with shots of attack choppers and bombed-out cities, the UN secretary-general discharged a one-and-a-half minute jeremiad in which we learned that inequality was deepening; global warming was out of control; xenophobia and nationalism were on the march, not to mention war, famine, pestilence and other afflictions, as though 2018 were beginning with a positive cavalry charge of apocalyptic horsemen.

He...