The projected cost of President Donald Trump's flagship missile defence initiative, known as the "Golden Dome," has ballooned to approximately $1.2 trillion over two decades — nearly seven times the original estimate of $175 billion — according to a new report from the nonpartisan Congressional Budget Office (CBO). The findings raise serious questions about both the financial viability and the technical feasibility of one of Trump's most ambitious defence proposals.

Trump first ordered the Pentagon to develop the system during his first week back in office in January 2025, describing it as a shield against "next-generation" aerial threats including ballistic missiles, cruise missiles, and hypersonic weapons. He envisioned a multi-layered network of ground-based radar systems, space-based sensors, satellite-mounted interceptors, and even experimental technologies such as space lasers and so-called "rods from God" — dense metal projectiles dropped from orbit at devastating speed. Trump has also linked the project to his interest in Greenland, arguing the Arctic island is strategically essential to the system's success. SpaceX and Lockheed Martin were awarded contracts worth up to $3.2 billion in April to develop space-based interceptor prototypes.

The CBO report, requested by Democratic Senator Jeff Merkley of Oregon, found that acquisition costs alone would exceed $1 trillion, with the space-based interception layer accounting for roughly 70% of procurement costs and about 60% of the total bill. Annual operating and support costs are estimated at around $8.3 billion. The agency cautioned that because key design details and the number of systems to be deployed remain undefined, producing a reliable long-term cost estimate is "extremely complex, if not impossible."

Critically, the report warns that even if fully built, the Golden Dome could be overwhelmed by a full-scale missile attack from a peer adversary such as Russia or China. Existing defence systems have not kept pace with the increasingly sophisticated weapons now fielded by potential rivals, officials have acknowledged. Senator Merkley was blunt in his assessment, calling the project "nothing more than a massive giveaway to defence contractors, paid for entirely by working Americans." Congress has so far allocated only around $24 billion for the project through a tax and spending bill, a fraction of the revised estimate.

The gap between the administration's promises and the CBO's projections underscores the enormous technical and budgetary hurdles ahead. Trump has expressed hope the system will be fully operational before the end of his term in January 2029, but analysts and former officials have warned that timeline is deeply unrealistic given that the project remains largely conceptual. The Golden Dome draws inspiration from Israel's multi-layered air defence architecture, including the Iron Dome, but the ambition to extend that model into space at continental scale represents a challenge of an entirely different magnitude.