Mr. Trump said in a social media post that Iran and other Middle Eastern countries had asked him to refrain from military action. The whiplash from war to tense calm has become routine as Mr. Trump strains to resolve the conflict with Iran that began in late February. This time around, at least one important U.S. ally appeared to have tried to steer Mr. Trump away from renewed attacks. It was the archetypal “forever war”, a phrase first coined during Vietnam. Dismayingly, the forever war lesson had to be learned all over again in Iraq, which the US and UK invaded in 2003 and departed, having caused huge harm for scant benefit, in 2011.