Bank runs are famously irrational things. Yet as the former Bank of England Governor Mervyn King once quipped, once they start, it’s rational to participate. The same goes for Donald Trump’s war against Iran. It was an irrational conflict to start. The President did not think anything through. He had no clearly-defined war goal, no exit strategy. But now that the war has started, with no success so far, it may well be rational to step up and fini