While living in Moscow in the 1990s, the one unchallenged certainty in a time of chaos was that no business could operate for long without a krisha, or roof, right down to the little English language bookstore my wife ran for while. This was the Russian euphemism for a protection racket — and Ukraine and Europe are now finding out what it can mean.

A krisha didn’t necessarily have to look or behave like a mafia boss from "The Godfather." Once the publishing company I worked for as the editor of a Moscow newspaper started making money, for example, it sold a 10% stake to a Russian conglomerate that was trying to clean up its image in the West. The arrangement was civilized, except when it wasn’t, but the purpose was clear.

The second certainty of that era was that your "roof” was the one person you didn’t want to fall out with, or they’d quickly become your most dangerous enemy. That’s the risk now faced by European governments from London to Berlin, and above all Kyiv, as the U.S. abandons its near-century-long role as benign krisha to the old continent. If that shift was in any doubt, take a look at Monday’s votes at the United Nations General Assembly in New York, or French President Emmanuel Macron’s pilgrimage as supplicant to the White House the same afternoon.