#more expensive

The White House’s $175-billion plan to protect the U.S. from nuclear annihilation will probably cost much more—and deliver far less—than has been claimed, says nuclear arms expert Jeffrey Lewis During a briefing from the Oval Office this week, President Donald Trump revealed his administration’s plan for “Golden Dome”—an ambitious high-tech system meant to shield the U.S. from ballistic, cruise and hypersonic missile attacks launched by foreign adversaries. Flanked by senior officials, including Secretary of Defense Pete Hegseth and the project’s newly selected leader, Gen. Michael Guetlein of the U.S. Space Force, Trump announced that Golden Dome will be completed within three years at a cost of $175 billion. The program, which was among Trump’s campaign promises, derives its name from the Iron Dome missile defense system of Israel—a nation that’s geographically 400 times smaller than the U.S. Protecting the vastness of the U.S. demands very different capabilities than those of Iron Dome, which has successfully shot down rockets and missiles using ground-based interceptors. Most notably, Trump’s Golden Dome would need to expand into space—making it a successor to the Strategic Defense Initiative (SDI) pursued by the Reagan administration in the 1980s. Better known by the mocking nickname “Star Wars,” SDI sought to neutralize the threat from the Soviet Union’s nuclear-warhead-tipped intercontinental ballistic missiles by using space-based interceptors that could shoot them down midflight. But fearsome technical challenges kept SDI from getting anywhere close to that goal, despite tens of billions of dollars of federal expenditures. “We will truly be completing the job that President Reagan started 40 years ago, forever ending the missile threat to the American homeland,” Trump said during the briefing. Although the announcement was short on technical details, Trump also said Golden Dome “will deploy next-generation technologies across the land, sea and space, including space-based sensors and interceptors.” The program, which Guetlein has compared to the scale of the Manhattan Project in past remarks, has been allotted $25 billion in a Republican spending bill that has yet to pass in Congress. But Golden Dome may ultimately cost much more than Trump’s staggering $175-billion sum. An independent assessment by the Congressional Budget Office estimates its price tag could be as high as $542 billion, and the program has drawn domestic and international outcries that it risks sparking a new, globe-destabilizing arms race and weaponizing Earth’s fragile orbital environment. To get a better sense of what’s at stake—and whether Golden Dome has a better chance of success than its failed forebears—Scientific American spoke with Jeffrey Lewis, an expert on the geopolitics of nuclear weaponry at the James Martin Center for Nonproliferation Studies at the Middlebury Institute of International Studies.