Congressional Budget Office says Trump’s Golden Dome could cost $1.2 trillion

Donald Trump sold Golden Dome as a $175 billion shield that would be finished by the end of his term. The Congressional Budget Office now says a missile defense system broadly consistent with Trump’s order could cost about $1.2 trillion to develop, deploy and operate over 20 years, in 2026 dollars.

That estimate points to a widening credibility gap around one of Trump’s signature defense ideas. The CBO said it could not calculate a true long-term price because the Pentagon has not released the program’s objective architecture, leaving lawmakers to debate a national security project with major implications for the budget and for the defense industry without a full public design.

To fill that gap, the CBO modeled a notional system with four interceptor layers: a space-based layer, two wide-area surface layers and a surface-based regional sector layer, along with sensors, communications and battle management systems. In that model, acquisition costs would total just over $1 trillion. The space-based interceptor layer alone would account for about 70% of acquisition costs and 60% of total costs, making it the dominant driver of the estimate.

The program’s official outline has already shifted from Trump’s first pitch. In January 2025, his executive order said the threat from ballistic, hypersonic and cruise missiles had grown more intense and complex over 40 years, and it called for proliferated space-based interceptors capable of boost-phase intercept. It also directed acceleration of the Hypersonic and Ballistic Tracking Space Sensor layer, tying the effort to Ronald Reagan’s unfinished missile-defense vision.

But the price tag has moved even within the administration’s own ranks. In March 2026, Space Force Gen. Michael Guetlein said the objective architecture cost had risen to $185 billion and that the project would extend into the 2035 timeframe. He also said the program was being simplified to keep costs down and that space-based boost-phase intercept could be dropped if it proved unaffordable.

Congress has pressed for more detail. Rep. Seth Moulton said the administration had classified nearly everything about the architecture and cost system, while Rep. Salud Carbajal questioned whether the $185 billion figure reflected the full system cost. The White House has proposed $17.5 billion for Golden Dome in fiscal year 2027, after putting $24.4 billion into the program through the fiscal 2026 tax-and-spending package.

The broader fight is no longer just about missile defense. Congressional researchers say Golden Dome raises hard questions about funding, industrial capacity, basing, launch platforms, manpower and strategic stability. The CBO’s estimate suggests the project could become either a working homeland defense system or an open-ended industrial and fiscal commitment whose final bill is still only starting to come into view.