On September 5th, American and Iranian military forces exchanged fire over vessels in waters near Iran's coast, crossing a threshold that decades of Gulf tension had approached but rarely breached. The Persian Gulf — a narrow passage carrying a third of the world's seaborne oil — has long been the stage for US-Iran rivalry, but posturing and proxy conflict are a different order of danger than uniformed personnel shooting at one another. What triggered the specific engagement remains unclear, and in that uncertainty lies the deeper peril: two nations with no diplomatic relations, no de-escalati