The Congressional Budget Office released an analysis on Tuesday that estimates that President Donald Trump’s Gold Dome missile defense scheme may cost $1.2 trillion over twenty years. Defense News notes that the CBO estimate is significantly more than the $185 billion the Trump administration has set aside for the project in its proposed fiscal 2027 defense budget. That gap is due, at least in part, to the fact that there are no publicly available plans from the White House nor the Pentagon about what the system will look like, “making it impossible to estimate the long-term cost of the GDA system being contemplated by DoD,” the report says.
The CBO based its estimate on a four-tiered defense system: a space-based layer, upper- and lower-level surface interceptor layers and multiple spread out surface interceptors, which would provide protection for all of the continental U.S. plus Alaska and Hawaii. This proposed system would be able to defend against multiple missiles fired simultaneously and would protect against threats from hypersonics, ballistics and cruise missiles. But the system could not successfully engage with a large-scale attack from a peer or near-peer adversary like Russia or China, according to the report.
As the cost estimate is based on the desired capabilities laid out in a January 2025 executive order, it doesn’t include funding for research and development of future technologies, nor does it take into account ground forces or a communication system necessary to make the proposed system work. This implies that the cost of the complete system could go even higher than the CBO estimate.