Donald Trump seemed to declare a clash of civilisations, in Warsaw last Thursday. Thereupon, he participated, uncomfortably, at the summit of the group of 20 leading economies. The G20 embodies the ideal of global community. A war of civilisations is the opposite. So which will it be?

The central remark in Mr Trump’s Warsaw speech was this: “The fundamental question of our time is whether the west has the will to survive. Do we have the confidence in our values to defend them at any cost? Do we have enough respect for our citizens to protect our borders? Do we have the desire and the courage to preserve our civilisation in the face of those who would subvert and destroy it?”

The speech took further the stance of two of Mr Trump’s senior advisers, HR McMaster and Gary Cohn, in an article published in May: “The world is not a ‘global community’ but an arena where nations, non-governmental actors and businesses engage and compete for advantage.” They argued that “America First does not mean America alone”. Yet the US was alone at the G20. Despite papering over of the cracks, the US was alone on climate and protectionism.