At the start of the war with Iraq, the Pentagon held almost 2,800 Patriot and THAAD missiles in its worldwide inventory. Almost two-thirds of the Patriot missiles and almost 40% of the THAAD missiles were expended by the end of July. CSIS estimates were based on publicly available Pentagon budget and acquisition documents, updated in some cases from recent press reports.

The CSIS estimates were not derived from leaks of classified information. Mark Cancian is a retired Marine colonel and principal author of the CSIS estimates.

Tom Karako, director of CSIS’s Missile Defense Project, said this represents a generational annihilation of the theater missile defense capability. He said there is no way to look at the situation and not see it as a setback.

The White House and the Pentagon have issued denials that a shortage of advanced defensive missiles exists. President Trump stated in August that the United States maintains overwhelming supply levels for many weapon systems. He said the U.S. has far more munitions than anyone in the world, and far more than needed.

He added that the military has unlimited supply of certain types of munitions while acknowledging constraints elsewhere. He said there are others where it’s a little bit tighter. The White House and the Pentagon have not challenged the Center for Strategic and International Studies figures.

A U.S. defense official stated last month that the shortfall of Patriot missiles in Europe was beyond critical. Former defense secretary Leon Panetta warned that the depletion affects strategic messaging. He said the U.S. must be strong enough to send a clear message that enemies should not try anything because the U.S. is a credible force.

He added that the U.S. is losing a lot of that credibility — and that’s dangerous. Michael C. Horowitz, senior fellow at the Council on Foreign Relations, described the inventory decline as a structural challenge for major militaries. He said this is the kind of situation in which great-power militaries like the United States struggle.

The Council on Foreign Relations stated in a report last month that the U.S. weapons arsenal no longer has the capacity to deter a Chinese attack against Taiwan. The Heritage Foundation forecast that the Pentagon’s inventory of missiles would run out within the first week of a Taiwan conflict. It will take years after replenishing the stocks expended in the Persian Gulf to build a credible deterrent against China.

Before the war with Iran, defense contractors produced about 620 Patriot missiles and 96 THAAD missiles each year. At current production rates, it will take at least three years to return the Patriot inventory to its prewar level. President Trump and Defense Secretary Pete Hegseth ordered an increase in interceptor production before the war with Iran began.

For much of August, U.S. forces did not respond with high-end missiles when Iran attacked oil tankers in the Strait of Hormuz. Patriot missiles were reportedly used to intercept incoming missiles during Iran's attack on U.S. bases in Jordan. The Pentagon has declined to confirm or deny reports that Patriot missiles were used to intercept incoming missiles in Jordan.

Congress has not yet funded the replenishment of depleted stores of advanced defensive missiles. The Pentagon has begun deploying relatively inexpensive anti-drone missile systems. Trump’s One Big Beautiful Bill Act included $7.7 billion for low-cost missile and drone programs last year.

More than 90% of the $7.7 billion allocated for low-cost missile and drone programs remains unspent 13 months after the bill's passage. Former President Biden gave several hundred Patriot missiles to Ukraine. The shortfall in advanced defensive missiles is larger than the number of Patriots given to Ukraine by former President Biden.

Why It Matters

The depletion of advanced interceptors reduces the United States' ability to defend allied territories and project power in contested regions. Rebuilding these stocks requires years of sustained production even after immediate combat needs subside. The discrepancy between public assertions of ample supply and internal assessments of critical shortfalls creates uncertainty for allies relying on U.S. security guarantees.

Reports indicate that the inventory decline exceeds previous transfers to other conflicts, suggesting a cumulative strain on the defense industrial base. The lack of congressional funding for replenishment combined with unspent allocations for alternative systems shows potential gaps in procurement strategy. These factors collectively influence how adversaries assess the risks of challenging U.S. interests in the Indo-Pacific and Europe.

Timeline

On July 4, 2025, the Secretary of the Interior began implementing Section 50203 of the One Big Beautiful Bill Act, making approximately 13,103,000 acres of Federal mineral estate available for coal leasing. On September 6, 2025, Trump’s One Big Beautiful Bill Act included $7.7 billion for low-cost missile and drone programs. Before the war with Iran, defense contractors produced about 620 Patriot missiles and 96 THAAD missiles each year as of February 27, 2026.

At the start of the war with Iraq on February 28, 2026, the Pentagon held almost 2,800 Patriot and THAAD missiles in its worldwide inventory. By the end of July 2026, the Pentagon's inventory of Patriot and THAAD missiles dropped to about 1,100. Also in July 2026, a U.S. defense official stated that the shortfall of Patriot missiles in Europe was beyond critical.

What's New

The Pentagon announced plans to buy almost 14,000 more Patriot Advanced Capability-3 and Terminal High Altitude Area Defense (THAAD) components. CSIS estimated the number of Patriot interceptors fell from 2,330 before the war to 1,030 when the April ceasefire took effect. Following the recent fighting, the stockpile is now estimated to be between 759 and 827, a decrease of at least 65% since before the conflict began. CSIS estimated the number of THAAD interceptors has declined by about 38%, leaving an estimated 234 to 278 interceptors. Defense Secretary Pete Hegseth has pushed out or blocked the promotions of at least 80 generals, admirals and other officials during his tenure.