Wars usually shape the political reality of those that orchestrate them. The other way around, when politics dictates the wars we fight, is often called “wag the dog”, after the figurative tail that is said to get the hound all a-jitter. It’s why, in the context of Donald Trump suddenly setting aside years of caution when it comes to lighting fires in the Middle East, the events of the last week have left foreign policy experts scratching their heads.