A proposed national missile defense architecture broadly aligned with US President Donald Trump’s ambitious Golden Dome missile shield project could become one of the costliest defense undertakings in American history, according to a new estimate released by the Congressional Budget Office (CBO).
The report estimates that the development, deployment, and operation of a notional nationwide missile defense system over a 20-year period could cost as much as US$1.2 trillion. The figure dramatically exceeds earlier estimates associated with the project and raises new questions about the strategic feasibility, technological practicality, and long-term affordability of a comprehensive American missile shield.
The projected cost is nearly seven times higher than the US$175 billion figure originally cited by President Trump when he unveiled the Golden Dome concept in a May 2025 executive order. Trump pledged at the time that the United States would complete the system within three years, before the conclusion of his current term in 2029.
The latest CBO assessment also sharply contrasts with statements made by Pentagon officials overseeing the initiative. Last month, Golden Dome program manager Gen. Michael Guetlein told lawmakers that the effort to establish the missile defense architecture would cost approximately US$185 billion.
The new estimate also dwarfs the Trump administration’s current budget allocation for the program. Washington has earmarked approximately US$79 billion over the next five years for the initiative, a fraction of the amount now projected by congressional analysts.
The revised cost assessment further represents a significant increase from a previous CBO estimate issued in May 2025. That earlier study, which accounted for reductions in launch costs and certain technological efficiencies, projected a price tag of approximately US$542 billion.
However, the latest report suggests that building a multilayered national missile defense system with space-based interceptors and extensive supporting infrastructure would require far greater investment.
According to the CBO, the notional national missile defense system was designed around four separate interceptor layers intended to provide overlapping defensive coverage against a wide range of aerial threats.
A space-based interceptor layer
Two wide-area surface-based layers, including upper and lower defensive tiers
A regional surface-based interceptor layer
The system would also require a sophisticated network of sensors, communications systems, and battle management infrastructure to coordinate defensive operations across all layers.
The proposed shield is intended to defend the United States against ballistic missiles, hypersonic weapons, cruise missiles, and other airborne threats launched by both regional adversaries and major military powers.
The CBO noted that the system could potentially counter limited attacks from countries such as North Korea or Iran, as well as smaller-scale strikes launched by near-peer rivals like China or Russia.
However, the report emphasized that the system would remain vulnerable to a full-scale strategic attack by a major nuclear power.
“The system could be overwhelmed by a full-scale attack mounted by a peer or near-peer adversary,” the report stated.
That conclusion undermines one of the central political narratives surrounding the Golden Dome initiative: the promise of creating an effective shield capable of fully protecting the United States from missile threats.
The CBO cautioned that even after investing more than US$1 trillion, the United States still could not guarantee complete protection against advanced missile attacks.
“Although the notional NMD system analyzed by CBO would be far more capable than the defenses the United States fields today, it would not be an impenetrable shield or be able to fully counter a large attack of the sort that Russia or China might be able to launch,” the report said.
The report identified the space-based interceptor layer as the single largest cost driver within the entire system.
Of the projected US$1.2 trillion total, acquisition costs alone would exceed US$1 trillion. The space-based interceptor network would account for approximately 70 percent of those acquisition costs and around 60 percent of total program expenses.
The proposed space architecture would require large constellations of satellites equipped with missile intercept capabilities, operating alongside missile warning and tracking systems.
Such systems are technologically complex and operationally demanding. They would require continuous maintenance, satellite replenishment, advanced launch infrastructure, and resilient communications systems capable of functioning during conflict.
Critics of space-based missile defense have long argued that the concept faces severe technical and economic limitations. Maintaining large constellations of armed satellites in orbit would require sustained investment over decades and could create vulnerabilities to anti-satellite weapons developed by rival powers.
The CBO report also warned that deployment of such a system could trigger strategic responses from adversaries.
According to the study, rival states could choose to expand their long-range missile inventories or develop more advanced countermeasures designed to penetrate or overwhelm the defense shield.
Such countermeasures could include decoys, maneuverable hypersonic glide vehicles, saturation attacks involving large missile salvos, electronic warfare capabilities, or anti-satellite weapons.
“The strategic consequences of deploying an NMD system with the capacity considered here are unclear because they hinge on an adversary’s perception of the defense’s capability and how that adversary chooses to respond,” the report said.
This concern reflects a longstanding debate in nuclear strategy. Analysts have often argued that large-scale missile defense programs can unintentionally accelerate arms races by encouraging adversaries to build larger and more sophisticated offensive arsenals.
Importantly, the CBO acknowledged that its US$1.2 trillion estimate does not include several major elements that could substantially increase the final cost.
The report excluded so-called “left-of-launch” capabilities, which involve destroying enemy missiles before they are launched. Such operations could include cyberattacks, long-range strikes, electronic warfare, or special operations missions.
The estimate also excluded directed-energy weapons such as high-energy lasers, which the Pentagon continues to research for missile defense applications.
Additionally, the report did not include ongoing missile defense modernization programs already underway within the US military.
Deployment of the Next-Generation Overhead Persistent Infrared (OPIR) satellite network
Expansion and operation of the ground-based missile defense site in Alaska
Research and development costs for emerging missile defense technologies
Additional communications infrastructure
Counter-drone systems
Land acquisition for interceptor sites
As a result, analysts believe the eventual cost of the Golden Dome initiative could significantly exceed even the trillion-dollar estimate.
Despite the CBO findings, Pentagon officials overseeing Golden Dome have defended their own lower cost projections.
Speaking before Congress last month, Gen. Michael Guetlein argued that external estimates fail to accurately reflect the architecture the Pentagon intends to build.
“When we start talking about the different cost estimates, the first thing I always say is, first of all, they’re not estimating what I’m building,” Guetlein 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.”
Guetlein said the project is pursuing a fundamentally different acquisition strategy aimed at reducing costs and accelerating deployment timelines.
According to the general, the Pentagon is emphasizing commercial innovation, streamlined procurement methods, and new operational concepts intended to improve affordability.
However, Guetlein also acknowledged that some aspects of the program could prove too expensive to implement.
He indicated that the Pentagon may avoid deploying space-based interceptors for boost-phase missile interception if the technology cannot be developed affordably and at scale.
“Because we are looking at the threats from a multi-domain perspective to make sure I have redundant capabilities and I don’t have single points of failure,” he said.
“So, if boost-phase intercept from space is not affordable and scalable, we will not produce it, because we have other options to get after it.”
“We are so focused on affordability. If we cannot do it affordably, we will not go into production,” he added.
Even if Golden Dome ultimately costs US$1.2 trillion, it would not be unprecedented in the history of major US defense programs.
The United States has repeatedly experienced dramatic cost overruns in complex weapons development projects.
One prominent example is the F-35 Joint Strike Fighter program. In the early 2000s, acquisition costs for the stealth fighter program were estimated at approximately US$200 billion to US$230 billion.
However, according to the Government Accountability Office (GAO), the program eventually exceeded original acquisition estimates by roughly US$183 billion.
Today, total lifecycle costs associated with the F-35 program through 2070 are projected to exceed US$2 trillion, making it the most expensive weapons program in American history.
The B-2 Spirit stealth bomber program experienced similar escalation.
Initially, the US Air Force planned to procure 132 bombers at an estimated unit cost ranging between US$280 million and US$500 million per aircraft.
In reality, the final per-unit cost reached approximately US$2.13 billion, forcing the Air Force to reduce procurement to just 21 aircraft after post-Cold War defense budget cuts.
The US Navy’s Zumwalt-class destroyer program followed a comparable trajectory.
The Navy originally intended to build 32 advanced stealth destroyers at a projected unit cost of approximately US$1.3 billion to US$1.8 billion.
Ultimately, only three ships were built, with final unit costs rising to roughly US$7 billion to US$9 billion per vessel.
These historical examples highlight the recurring difficulty of accurately estimating the cost of technologically advanced defense systems during their early planning stages.
The growing debate surrounding Golden Dome now extends beyond simple budgetary concerns.
Supporters argue that the evolving missile capabilities of China, Russia, North Korea, and Iran require the United States to pursue a more comprehensive homeland missile defense architecture.
The rapid development of hypersonic weapons and maneuverable missile systems has intensified concerns among US defense planners about vulnerabilities in existing missile defense networks.
Critics, however, argue that the enormous financial burden associated with a national missile shield may ultimately provide only limited strategic advantages.
If the system cannot reliably defend against a large-scale attack by a major nuclear power, opponents question whether the investment can be justified, particularly at a time of growing US national debt and mounting fiscal pressures.
The project also raises broader geopolitical concerns. Large-scale missile defense deployments have historically been viewed by Russia and China as potentially destabilizing because they could weaken the credibility of nuclear deterrence.
As a result, deployment of Golden Dome could further intensify strategic competition among the world’s major powers.
The Golden Dome initiative remains in the conceptual and planning phase. However, the new CBO estimate has dramatically reshaped the public debate surrounding the project.
Whether the program ultimately evolves into a scaled-down missile defense architecture or expands into a trillion-dollar strategic shield, the financial, technological, and geopolitical implications are likely to shape US defense policy for decades to come.
