The US has overwhelming military power. Yet the battle has moved to oil routes, alliances and domestic politics – where Tehran is testing western unityDonald Trump would like you to know that he is winning the war with Iran. So comprehensively, in fact, that he now needs Nato’s help. The western alliance, he warns, will have a “very bad” future if its members refuse. Germany’s defence minister had a brisk reply: this is not our war. Meanwhile, tankers pile up outside the strait of Hormuz as Britain promises, in an understated way, to keep “looking” at its options. Mr Trump has found out that starting a war without a coalition of the willing is easier than finishing one with it.Along with Israel’s Benjamin Netanyahu, the US president started with an illegal attack on Iran in which the country’s supreme leader was assassinated. American forces have established overwhelming military superiority. By hitting military targets but sparing key oil f...