International Physicians for the Prevention of Nuclear War, Physicians for Social Responsibility, and Back from the Brink released a scientific report on Tuesday finding that a proposed U.S. missile defence system (dubbed the ‘Golden Dome’) would leave tens of millions of Americans vulnerable to nuclear attack while costing trillions of dollars and accelerating the global arms race.

The report, which came amid the ongoing review conference on the Nuclear Non-Proliferation Treaty, pointed out that a comprehensive system capable of addressing modern threats could cost as much as $3.6 trillion and yet would not be 100 per cent effective, leaving hundreds of millions of Americans in target zones.

Key report findings stated that even in a best-case scenario, more than 300 warheads would penetrate the defence system, 132 major U.S. cities could still be successfully targeted and 75 million Americans live in areas that would be totally destroyed.

The report also evaluated claims stemming from President Donald Trump’s May 20, 2025 announcement that the U.S. could build a near-100 percent effective missile defence system within three years at a cost of $175 billion.

However, the report, drawing on research including the American Enterprise Institute, insisted that such effectiveness “is unrealistic and far more costly”.

“These findings make clear that there is no technological shield capable of protecting the United States from nuclear war,” said Ira Helfand, the report’s principal author. “Even a highly effective system would still result in societal collapse and mass casualties.”

The report also highlighted global impacts.

It noted that nuclear firestorms could inject massive amounts of soot into the atmosphere, lowering global temperatures and triggering a famine that could kill up to 1.4 billion people within two years.

The authors warned that pursuing such a system would create a false sense of security while fuelling a new nuclear arms race as adversaries expand arsenals to overwhelm U.S. defences.

The report called on the U.S. government to begin negotiations with other nuclear-armed nations toward a “verifiable agreement to dismantle global nuclear arsenals”.