Years ago, when I was teaching, I regularly subjected my students to a lecture titled “The Four I’s.” Confronted with an essay using the words “impossible,” “inconceivable,” “inevitable,” or “irreversible,” I suggested, one was best advised to stop right there and do something more constructive. This was because the modern history of the Middle East—with its shape-shifting alliances and roller-coaster politics—offered no justification for the use of any such words.