President Donald Trump’s grand vision for the “Golden Dome” national missile defense system may cost taxpayers hundreds of billions of dollars more than originally expected, according to a new estimate by the Congressional Budget Office (CBO), which found that the system could cost $1.2 trillion to build and operate for 20 years.
The CBO conducted its analysis based on Trump’s 2025 executive order directing the Defense Department to draft plans for a ground- and space-based system to detect and stop missile attacks. The CBO estimates that acquisition costs for the project “would total just over $1 trillion,” with the space-based interceptor layer making up 70 percent of that total. Trump originally estimated the project would cost $175 billion and be “fully operational” by the end of his term, a timeline some say is unrealistic.
The CBO’s new report does not project when the Golden Dome could be completed, but it says the space-based interceptors “will probably take at least several years to develop.” It also notes that the project’s timeline depends on the industrial base’s ability to “produce enough interceptors and radars, particularly of the types that have been consumed in large numbers or destroyed in the Iran war.”
Proponents of the Golden Dome have pitched the project as an American version of Israel’s Iron Dome, but there are key differences between the systems. The U.S. would need to defend itself against intercontinental ballistic missiles. But, as William Hartung, senior research fellow at the Quincy Institute for Responsible Statecraft, has noted, Israel’s Iron Dome “would be of no use against an incoming intercontinental ballistic missile.”
“Long-range interceptors have failed many tests, and those tests were considerably less rigorous than an actual attack would be,” Hartung told Responsible Statecraft last year. “That a new initiative would do better is both unproven and unlikely.” The implementation of a Golden Dome would be even more difficult, given that it would have to protect the entire continental United States, Alaska, and Hawaii, a much larger area than Israel.
Meanwhile, critics of the project have compared it to Ronald Reagan’s failed Strategic Defense Initiative (SDI), nicknamed “Star Wars.” In 1983, Reagan announced his ambitious plan to make a space-based missile defense program that could “protect the country from a large-scale nuclear attack.” But the project was not technologically feasible, and the Clinton administration ended the project 10 years and $30 billion later.
In June 2025, Sen. Jeff Merkley (D–Ore.) referenced SDI’s failures in a letter to the CBO director, warning that “the risks of repeating history are real.” Given the Golden Dome project’s “sweeping scope and strategic risks involved,” he asked the CBO to investigate its costs. He noted the plan raised more than practical concerns, and it also represents a major U.S. shift in U.S. foreign policy “by explicitly aiming to counter the strategic nuclear forces of Russia and China.”
Reason’s Matthew Petti echoed these concerns in 2025, writing, “America’s best defense against nuclear war so far has been mutually assured destruction.” Building a national missile defense system would undermine this principle, he explained.
“During the Cold War, trying to build a missile defense system was actually considered an escalation because it would undermine everyone else’s ability to retaliate for a first strike,” Petti wrote.
Petti also noted that Russia and China issued a joint statement last May warning that the project could destabilize global stability, and it “has high potential to provoke a regional and global arms race.”
Funding a potentially globally destabilizing multi-trillion-dollar project may seem absurd, but it’s par for the course for an administration attempting to convince Americans that a $1.5 trillion Pentagon budget is necessary. But with zeal for military spending remaining an issue that enjoys bipartisan support, Americans shouldn’t be surprised if Congress ends up financing the project. In fact, they have already begun to: Last summer, lawmakers appropriated more than $24 billion for the Golden Dome through the One Big Beautiful Bill Act.
