As US President Donald Trump flew home from a fractious Nato summit in Turkey, he was poised to resume the war with Iran, whose leaders he labelled “sick” and “scum”. Trump also complained about European leaders’ failure to spend enough on arms, support him in Iran and recognise the need for the US to take control of Greenland. The sense of rising global conflict has been palpable this week. What clearly showed at the summit of the transatlantic security alliance was confirmed by the latest...