(The Center Square) – The nonpartisan Congressional Budget Office said Tuesday that President Donald Trump’s Golden Dome missile defense shield could cost American taxpayers as much as $1.2 trillion over 20 years, far exceeding the Pentagon’s public estimate of roughly $185 billion through 2035.
The estimate, requested by Senate Budget Committee Ranking Member Jeff Merkley, D-Ore., found acquisition costs alone could top $1 trillion, with a planned space-based interceptor layer accounting for about 60% of the total.
The CBO cautioned that the estimate carries substantial uncertainty because the Pentagon has not publicly released details about the system’s final architecture or force structure.
Instead, the agency said it based its analysis on the requirements outlined in Trump’s January 2025 executive order directing the Pentagon to defend against “ballistic, hypersonic, advanced cruise missiles, and other next-generation aerial attacks from peer, near-peer, and rogue adversaries.”
That uncertainty appears to be at the center of the gap between the CBO’s estimate and the Pentagon’s projections.
Just two weeks ago, Space Force Gen. Michael Guetlein, the director of Golden Dome for America, told the Senate Armed Services Strategic Forces subcommittee the program would be delivered “on time and on budget” at about $185 billion through 2035.
The Pentagon has not publicly explained whether that figure reflects a narrower system than the one envisioned in Trump’s executive order, excludes certain long-term costs or relies on funding streams outside the program itself.
When asked about outside cost estimates during a House Armed Services subcommittee hearing last month, Guetlein rejected comparisons that projected significantly higher totals.
“They are not estimating what I’m building,” he said. “They are estimating the modernization or the continuation of the legacy systems that we already have and they just take the cost of a legacy system and they multiply it out and they get these really large numbers and they say, well, that must be it. That is not what Golden Dome is doing.”
Congress has already approved $25 billion for Golden Dome in last year’s reconciliation bill, a fraction of the CBO’s projected long-term cost. The Pentagon is now asking lawmakers to approve an additional $17 billion in a new reconciliation package this year.
The CBO also warned that even a fully built Golden Dome system would not provide an impenetrable shield against large-scale missile attacks from adversaries such as Russia or China and could encourage those countries to expand their offensive missile arsenals in response.
“The system could be overwhelmed by a full-scale attack mounted by a peer or near-peer adversary,” according to the CBO report. “Furthermore, ‘fully engage’ is not the same as ‘fully defeat’ because no defense works perfectly every time.”
In a September 2025 working paper for the American Enterprise Institute, defense analyst Todd Harrison described the concept as “technically feasible and strategically sound overall” but warned it could become “the poster child for waste and inefficiency in defense” if Congress eventually cancels the program before completion.
Merkley called the program “a massive giveaway to defense contractors paid for entirely by working Americans,” adding that it “will do little to advance American national security.”
The House Armed Services Committee’s Republican press office did not immediately respond to a request for comment after 5 p.m. Tuesday.
A Pentagon spokesperson referred questions about the CBO estimate to Guetlein’s April 15 House testimony, in which he said outside cost estimates “are just not estimating what I am building.”
