The consequences of the war with Iran are now showing up far beyond the Middle East. U.S. Patriot missile stocks in Europe are reportedly “beyond critical,” with the U.S. having burned through roughly 65% of its Patriot interceptor inventory during the conflict, while the Pentagon is extending Middle East deployments into 2027 and maintaining roughly 50,000 troops in the region, alongside 19 warships and other assets.
Washington resumed major strikes against Iran after a month-long lull in late August, marking the most significant fighting since July and triggered a fresh spike in oil prices and bond yields before escalating further into direct strikes on Iranian oil tankers and a naval blockade in early September. That phase has since eased: direct exchanges between the two sides largely tapered off through mid-September, and Trump said on September 16 that he hoped the war was nearing its end, even as it entered its seventh month with no firm resolution in sight.
The war’s costs continue to surface in other ways. The Washington Post reported on September 18 that five U.S. officials familiar with internal Pentagon casualty data put the number of American fatalities at 22, four more than the Defense Department’s publicly recorded 18.
Each cycle of escalation and pause draws further on the resources, forces, and strategic attention the United States needs elsewhere. The central question is becoming one of military sustainability. How much capacity can Washington expend in one theater while preserving enough margin to deter or respond to the next crisis?
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It is tempting to read the war that began on February 28 as a story about Iran — whether its regime survives, whether the Strait of Hormuz reopens, and whether its nuclear program is gone. The more consequential story may be about exhaustion across several dimensions of American power. Individually, none is fatal. Together, they expose the limits of a way of war that has depended for three decades on substantial inventories, ready forces, secure regional infrastructure, and the ability to concentrate U.S. military power when a crisis demands it.
The First Margin: Munitions
The first margin is the most literal one. Munitions. In a late-July analysis, the Center for Strategic and International Studies put a number on the broader damage: the THAAD missile inventory was down nearly half since February, and the analysis warned it would take three or more years to rebuild those stocks to pre-war levels. No more recent public estimate of interceptor inventories has surfaced since.
That accounting is no longer the province of outside analysts alone. In a first-of-its-kind mandatory report to Congress released in mid-September, the Pentagon’s own inspector general confirmed that munitions expenditure has produced “strategic inventory shortfalls” and exposed bottlenecks in the industrial base’s ability to resupply them. The report put the war’s cost through June at $33.4 billion, including $22.3 billion spent on munitions alone, and documented the destruction or damage of dozens of aircraft — among them four F-15s and an F-35 — along with hundreds of buildings at U.S. bases across eight countries in the region. The findings directly contradict repeated assurances from President Trump and Defense Secretary Pete Hegseth that no such shortage exists.
That raises a basic defense-planning problem. Having enough inventory to sustain today’s campaign is only one measure of military power. The more important question is whether the United States can replenish what it expends while preparing for another contingency. A prolonged campaign therefore consumes time as well as missiles, creating a recovery period during which the military has less flexibility to respond elsewhere.
The Second Margin: Force Availability
The second margin is force availability. The decision to pull the USS George Washington from the Pacific to replace the long-deployed USS Abraham Lincoln in the Middle East illustrates the mounting opportunity costs of the Iran conflict. It is more than a deployment decision. Moving a carrier from one theater to sustain another consumes strategic capacity even when no ship is lost and no missile is fired. It also raises a growing credibility problem for the United States, as open-ended operations in the Middle East consume forces and attention that Washington says it needs to deter China in the Indo-Pacific.
The pattern extends across the broader Indo-Pacific commitment. President Trump’s decision to scale back joint military drills with South Korea and his overture to Kim Jong Un, alongside his preference for concentrating U.S. attention on the Western Hemisphere, point in the same direction. Sustaining the Gulf commitment increasingly comes with opportunity costs elsewhere. America retains the power to fight in more than one theater, but each additional commitment reduces the unused capacity available for the next one.
The Third Margin: Infrastructure
A third margin is the resilience of the infrastructure that supports U.S. power. The Strategic Petroleum Reserve is one example. Washington has used it to blunt the price shock from a closed Hormuz. The reserve has fallen to 298.7 million barrels, its lowest level since January 1983, down from roughly 415 million barrels before the war began, and federal auditors now warn the pace of withdrawal risks damaging the underground salt caverns that store it. A tool built to cushion America from this kind of energy shock is itself running down in the middle of the shock it was designed to absorb.
The same problem is visible in the Gulf basing network the U.S. has relied on for three decades. Iranian missiles destroyed the combined air operations center at Al Udeid Air Base in Qatar in the war’s opening weeks. The U.S. basing pattern across the Gulf was built for fights against terrorist groups that could not hit back. It now places American forces within easy range of a state that can. Gulf officials themselves likely have drawn the same conclusion and are now folding demands for more consultative, less automatic security arrangements into their thinking about the future.
The Pentagon’s inspector general later confirmed that the damage from the war’s opening weeks extended well beyond Al Udeid, with strikes destroying or damaging hundreds of buildings at U.S. installations across Kuwait, Bahrain, Qatar, the UAE, Saudi Arabia, Iraq, Oman, and Jordan, and hitting the U.S. Navy’s main logistics hub in Bahrain.
The Fourth Margin: Political and Strategic Endurance
A fourth margin is political and strategic endurance. A Reuters/Ipsos poll from late July found that only one in three Americans supported the war, with 69% saying the president had not clearly explained what it was meant to accomplish, and a companion AP-NORC survey conducted the same week found that roughly two-thirds of Americans considered the war not worth fighting. Support has eroded further since: by late August, Reuters/Ipsos found backing had fallen to a new low of 31%, driven largely by softening Republican support, while Trump’s own approval matched the weakest mark of either of his terms. Nate Silver’s polling tracker now puts the spread at roughly 34% support to 58% opposition as the war enters its seventh month — a trajectory Republican strategists openly describe as a drag on the party’s chances of holding Congress in the November midterms.
The confusion over goals also affects the credibility of presidential signaling. Since February, Donald Trump has moved through nearly every register available to a wartime president. In March he declared there would be no deal short of Iran’s unconditional surrender, then days later ordered a five-day suspension of strikes on Iranian power infrastructure while insisting Iran wanted a deal. By April the two sides had signed a ceasefire brokered by Pakistan.
By summer the ceasefire had collapsed and strikes had resumed alongside a naval blockade. As the war entered its sixth month, Trump said he intended to declare the Strait of Hormuz U.S. territory once Iran is “defeated.” Each individual pivot might be defensible as tactical flexibility. The cumulative effect, visible in the polling and in allied reactions, is that Washington’s objectives have become harder for the public and partners to read.
The same uncertainty affects regional partners. Trump’s threat to bomb Oman if the Gulf state “gets in the way” of U.S. efforts to strike a peace deal with Tehran turned a longstanding regional partner into a potential object of coercion. Such threats may be intended to demonstrate resolve. They also make U.S. intentions harder for partners to anticipate and harder for them to trust.
The Strategic Consequences
The final margin is the strategic environment the war itself is creating. Iran has spent the conflict showing that reopening the Strait of Hormuz on its terms would not restore the old status quo but create a new source of leverage. Tehran has sought to charge as much as $2 million per voyage, publicly framed as war reparations. President Trump himself described an American-brokered version of the toll “a beautiful thing.”
When Oman proposed a joint regional management system modeled on the Strait of Malacca that would have diluted Iran’s unilateral control, Tehran rejected it. Major shipping lines say they will not resume normal transits until any deal proves durable, turning longer, costlier voyages around the Cape of Good Hope from an emergency detour into a standing feature of global shipping. Whatever emerges, “reopening” will not mean a return to the Strait of January.
Taken together, these pressures describe a military and strategic model built for an era that assumed deep magazines, a substantial strategic reserve, relatively secure regional basing, patient domestic support, and an adversary too weak to impose sustained costs. The 2026 war with Iran is testing that model against a state that can shoot back for months on end. The model is visibly straining under the test, running down several of its supporting pillars simultaneously and in public.
The more pressing question is what happens if Washington needs to fight a comparable war again, against Iran or against a more capable rival, before the interceptors are rebuilt, the reserve is refilled, the bases are hardened, and political support has recovered. The question becomes even more consequential if the United States must deter China or respond to a crisis in the Indo-Pacific at the same time. Military power is measured partly by what the Pentagon can put into a fight today. Strategic power also depends on what it can replenish, sustain, and keep available for tomorrow. On the evidence of the last six months, that margin is becoming a scarce resource.
