Pakistan, Oct. 3 -- There is a cruel arithmetic to Pakistan's economy. Two waterways most Pakistanis will never see, one about 21 miles wide at its narrowest, the other barely 18, now help decide what a family in Sargodha pays for flour, what a weaver in Faisalabad pays to run his looms, and what arrives on an electricity bill in Karachi.

That is not rhetoric. It is the transmission mechanism, and it has been running at full speed since February.

Before the current disruption, roughly 21 million barrels of oil and petroleum products moved through the Strait of Hormuz every day, close to a fifth of global petroleum consumption. According to the US Energy Information Administration, that collapsed to about 4.9 million barrels per day in t...