Derek Harvey was a man who saw things coming. He had warned of Al Qaeda when most chose to ignore it. He had seen the Sunni insurgency rising when most chose to deny it. The former Army colonel had made his reputation by learning the lay of the land. In Iraq that meant sleeping on mud floors and digging into documents to figure out where the threat was coming from. It was hard to imagine anyone better qualified to serve as President Trump’s top Middle East adviser at the National Security Council than a man who had been on the...