Pakistan, May 27 -- There are hours in history when a country's importance is not measured by the noise it makes, but by the danger it helps avert. In the latest round of US-Iran tensions, Pakistan found itself in precisely such an hour. At that moment, Pakistan did not posture. It performed.

This was not diplomacy for applause. It was diplomacy with purpose. Islamabad understood what was at stake because Pakistan has lived too close to conflict for too long to treat escalation as an abstraction. A war involving Iran and the United States would not have remained confined to military briefings or distant capitals. It would have shaken energy markets, unsettled the Gulf, inflamed regional sentiment, threatened trade routes and placed addit...