At first glance, Iran's surprise missile strike on a US base in Jordan earlier this week appeared difficult to explain. The attack effectively ended the fragile pause in direct US-Iran fighting and prompted Washington to resume strikes inside Iran. It was also unusual. If Tehran's priority had been a ceasefire, the strike is difficult to explain. But if Iranian leaders judge that a controlled confrontation could offer greater strategic leverage, the decision becomes more understandable. One possible explanation is that Tehran believes that, despite its risks, a limited war serves its interests better. Today, neither side appears ready for an...