One week. That was how long the informal understanding between Washington and Tehran had lasted before it faced its most dangerous test. On Thursday, a drone struck a cargo ship navigating the Strait of Hormuz — the narrow waterway through which roughly a fifth of the world's traded oil passes — and the United States attributed the attack to Iran. By Friday, American forces had responded with strikes of their own, sharply escalating a confrontation that both governments had, only days earlier, appeared to be cautiously stepping back from.

The Strait of Hormuz has long functioned as both an economic lifeline and a geopolitical pressure point. Sitting between the Iranian coast and the Omani peninsula, it is one of the few chokepoints through which tankers carrying Gulf oil must pass on their way to markets in Asia and Europe. Any sustained threat to navigation there reverberates almost immediately in commodity prices and insurance premiums from Tokyo to Rotterdam. It is precisely this leverage that has made the strait a recurring instrument of Iranian signalling in moments of diplomatic strain.

What makes the current episode particularly consequential is its timing.