The war has become an exemplar of Mr. Trump’s chaotic, ego-driven approach to the presidency. He has relied for advice on a smaller circle of aides than past presidents did when ordering military action and eschewed the careful process intended to call attention to objections and potential problems. He has made ridiculous and contradictory public statements, including a claim that the war has nearly achieved its goals. He has tried to mislead the world about the tragic deaths of dozens of Iranian schoolchildren, which were caused by a mistargeted American missile. Almost daily, he demonstrates why he cannot be trusted with the most consequential matters of government.