CBO Says ‘Iron Dome for America’ Would Cost About $1.2 Trillion Over 20 Years

The Congressional Budget Office said Tuesday that a U.S. national missile-defense system broadly matching the goals of the “Iron Dome for America” executive order would cost about $1.2 trillion over 20 years, a far higher figure than the administration has publicly discussed. CBO stressed that it was not pricing a finalized Pentagon plan: It built a notional system because the Defense Department has not released a detailed final architecture.

The estimate, published May 12 in a report titled “Potential Costs of a National Missile Defense System,” contrasts sharply with President Donald Trump’s roughly $175 billion public cost figure when he announced the plan in May 2025. It also exceeds the roughly $185 billion estimate cited in March by Gen. Michael Guetlein, the head of the Office of Golden Dome for America, who said, “We were asked to procure some additional space capabilities. So we are at $185 billion for the objective architecture ...”

CBO said its modeled system “would cost about $1.2 trillion” to develop, deploy and operate for 20 years, with all figures in 2026 dollars. Its table puts the total at $1.191 trillion, including $1.025 trillion in acquisition costs. The office said the figures are higher in part because it modeled a fully layered homeland defense system consistent with the executive order’s ambitions and counted long-term operations and sustainment, not just initial procurement.

That distinction is central to the comparison. CBO said it had to create its own notional architecture because the Pentagon had not released an “objective architecture.” It based the model on Executive Order 14186, signed Jan. 27, 2025, which directed the Defense Department to prepare a missile-defense architecture and implementation plan aimed at countering ballistic missiles, hypersonic weapons, advanced cruise missiles and other next-generation aerial attacks. The order said, “Within 60 days of the date of this order, the Secretary of Defense shall …” begin laying out that plan.

In CBO’s notional design, the system has four interceptor layers: a space-based interceptor layer, two wide-area surface layers — upper and lower — and a surface-based regional sector layer. It also includes sensors, communications and battle-management systems.

The biggest driver by far is the space-based interceptor layer. CBO estimated that piece would cost $723 billion to acquire, accounting for about 70% of acquisition costs and about 60% of total 20-year costs. The report described that layer as a 7,800-satellite constellation capable of engaging a raid of 10 intercontinental ballistic missiles, or ICBMs, launched nearly simultaneously.

CBO said the architecture it modeled could fully engage an attack by a regional adversary such as North Korea, or a small-scale attack by a peer or near-peer power. But it said the system could be overwhelmed by a full-scale attack from a peer or near-peer. The office also cautioned that “fully engage” is not the same as “fully defeat.”

The budget office emphasized that its estimate depends on the architecture it chose to model and would change if the system were scaled up or down. In other words, the report is best understood as an independent cost estimate for a broad, layered homeland shield aligned with the executive order, not a bill for a final Pentagon design.

That caveat matters as the Pentagon’s effort, now called Golden Dome for America, remains in the early stages. CBO said the FY2027 president’s budget includes a Golden Dome for America Fund with near-term funding averaging roughly $15 billion a year over several years, far below CBO’s long-run estimate. The office said that gap could reflect differences in time horizon, scope or accounting across funding accounts.