Six months into the Iran war, the United States quietly has started to pose a question it hasn't asked for decades: Does it really need so many bases in the Persian Gulf? The Pentagon's policy office has initiated an early review of America's military presence in the region, along with the Joint Staff and US Central Command, and it could significantly change how, and where, some 40,000 troops are deployed in the years to come, according to a report that was picked up by wire services throughout the region and mirrored across the country by The Washington Post.

No one in Washington is saying this is a withdrawal and Defense Secretary Pete Hegseth has not ordered a posture review. One senior Pentagon official said it was merely “wisdom of the crowd” in the form of “thinking through what they need to do if something like this actually happens.” However, the timing speaks for itself. Over the past six months, since the United States and Israel began their campaign targeting Iran, they are said to have suffered the destruction or damage of more than 200 American facilities in the Gulf region by Iranian ballistic missiles and one-way attack drones. In March, six US military personnel died in one attack on a US base in Kuwait, and the death toll is now estimated to have risen to 19 and the injuries to hundreds by August. The Pentagon has already fired thousands of high tech interceptors from its Patriot and THAAD arsenal to protect bases built without this capability, and the U.S. military has responded with more than 13,000 missile attacks against Iran.

The maths in the rethink is harsh. Now the Pentagon's estimate of the cost of the war through the end of September is approximately 37.5 billion dollars, with the cost of rebuilding any bases damaged by Iran not included. In April, at the beginning of the fighting, the American Enterprise Institute estimated that that reconstruction bill would be approximately 5 billion dollars, and the actual cost is likely to be much higher now. What it means to rebuild in the same places at all seems to be a more fundamental question that officials are asking as they try to determine how to repair what was lost as a result of that math.

The location of the debate is revealing. The headquarters of the US Fifth Fleet is in Bahrain. Kuwait is home to significant Army and Air Force installations. The war has made these weaknesses evident in stark terms, both are in the reach of Iran's short and medium-range missiles. One idea being considered is to close or reduce capacity at facilities located in Kuwait and redeploy forces from Bahrain, UAE and Jordan further west towards the airbase in Ovda in Israel or the Red Sea coast in Saudi Arabia, where there is more distance between American personnel and Iranian launch sites. One U.S. official with knowledge of deployment planning told me succinctly: Iran still believes that American troops are where they've always been and they're not. Even the Israel choice is fraught with complications. There is also some resistance within the administration to a larger U.S. footprint there, because they don't want to be so near to Israeli intelligence services that they risk being exposed as part of their counterintelligence efforts.

Beneath the logistics is a real conflict within the administration, between those who want to lean in toward more sustained forward deployment in the Middle East and a more rule-of-thumb element that's long complained that Washington's security guarantees are overextended, and ought to be focused on home defense and deterring a much bigger adversary in China. This argument has been bubbling away for years; a war that has cost tens of billions of dollars and has been devastating the very foundations that would project American power has breathed new life into it.

The economic benefits go far beyond the Pentagon's bottom line. The war risk insurance has fluctuated wildly throughout the conflict, rising from about a quarter of a percent of hull value before the war to from 3 to 10 per cent at war's peak, and becoming as high as 10,000,000 dollars per voyage for a big tanker transitting the Strait of Hormuz through which nearly one fifth of the world's seaborne oil trade was once carried. Freight costs to carry crude oil from the Gulf to Asia have followed suit and are now at around 78 dollars a tonne, up from a high in March of around 140 dollars a tonne, and above pre-war levels despite a recent decline. Independent estimates have put at up to 85 percent of the seaborne exports from the Gulf would have no other choice but to go around the Strait if it were meaningfully constricted: regional pipeline bypass capacity in the UAE and Saudi Arabia covers only a fraction of volumes, while countries such as Bahrain, Kuwait and Qatar have no bypass route at all.

This is the awkward setting in which Gulf capitals are watching Washington's deliberations. Despite their own defense spending having risen significantly over the last few years Saudi Arabia's having approached 64 billion dollars, for instance, and UAE's above 27 billion both have always sought to build their defense plans around the American security umbrella and have long treated it as a cornerstone of their security plans. It takes months to build out a missile defense system, air power and surveillance system that can replace a smaller American presence. It is one that takes years and during that time, any possible drawdown by any American would coincide with Iran's recent proof it was willing and able to strike deep into the Gulf territory. The decision in Washington will affect not only the military map of America but the cost of oil, shipping and the security decisions of six governments for a long time to come as the calculation now being made in the Pentagon policy office is underway.