T he war in Iran has reaffirmed two truths. One is that the United States is blessed with the most professional and effective military in the world. The men and women of the American armed forces can conduct missions of almost any size with formidable competence, from special operations to seize a rogue-state president to a large-scale war. The other truth is that the Trump administration, when it comes to strategy, is incompetent. Strategy is about matching the instruments of national power—