Senator Raises Alarms Over Feasibility and Oversight of Expansive Missile Defense Proposal

WASHINGTON — A tense exchange at a Senate Armed Services Committee hearing this week highlighted growing bipartisan concerns about the scientific feasibility, cost, and oversight of the Biden administration’s proposed “Golden Dome” missile defense system — a sprawling, multi-layered shield that could cost up to $1 trillion and is intended to intercept a full-scale intercontinental ballistic missile attack.

The system, which the administration has described as an essential modernization effort, is envisioned as a network of ground-, sea-, and space-based sensors paired with interceptors capable of responding to complex threats, including hypersonic glide vehicles and decoys. But on Tuesday, Senator Mark Kelly, Democrat of Arizona and a former Navy combat pilot, engineer, and NASA astronaut, pressed Defense Secretary Pete Hegsth on whether the technology underpinning the proposal is physically achievable.

“Are we building real security,” Mr. Kelly asked at one point, “or buying an illusion?”

From the outset, he questioned whether Golden Dome could ever deliver the reliability it promises. “You’re talking about hundreds of ICBMs launched simultaneously, with multiple re-entry vehicles, hypersonic glide bodies, and thousands of decoys,” he said, outlining a scenario widely viewed by defense analysts as among the most difficult challenges in modern warfare. Missile defense at that scale, he noted, would need to function at near-perfect accuracy — “four nines,” or 99.99 percent reliability.

“This is a very hard physics problem,” Mr. Hegsth acknowledged, repeatedly emphasizing that the department aimed to integrate existing technologies while “building toward future capabilities” as rapidly as possible.

Still, the secretary did not commit to any specific performance benchmarks, instead offering broad references to command-and-control networks, sensor architecture, and a “multi-layered” approach designed to counter a range of adversaries, including China and Russia.

Mr. Kelly pushed back, insisting that the administration had yet to demonstrate that the fundamental science behind the system — particularly the ability to discriminate real warheads from decoys at high velocity — could support the project’s ambitions. “I am not sure the physics can get there on this,” he said.

The exchange underscored a long-standing debate in Washington about the limits of missile defense. Since the 1980s, successive administrations have launched programs aiming to neutralize nuclear attacks, yet no nation has succeeded in reliably intercepting a coordinated, high-volume ICBM salvo under real-world conditions. Despite decades of investment, most tests have taken place in controlled environments with advance notice of launch time, trajectory, and target.

The hearing took a sharper turn when Mr. Kelly highlighted another concern: recent cuts to the Pentagon’s Office of the Director of Operational Test and Evaluation, which oversees independent assessments of major defense systems. The administration has eliminated more than half the office’s staff, a move Mr. Kelly suggested could jeopardize the integrity of future testing, including the evaluations Golden Dome would require before being fielded.

“You cut most of the staff of the people who are going to make sure this thing works before we make it operational,” Mr. Kelly said. “You need something approaching 99.99 percent reliability, and you cut the office responsible for verifying whether that reliability exists.”

Mr. Hegsth described the reductions as part of a streamlining effort to eliminate redundancies. He insisted the cuts were not linked to Golden Dome and said the department continued to rely on scientific expertise across the military and intelligence community.

But Mr. Kelly argued that the scale of the proposed system — with a projected cost starting at $25 billion in the first year and potentially reaching half a trillion dollars or more — required a more rigorous scientific review than the administration has assembled. “Before we spend hundreds of billions,” he said, “put together a group of people who can tell you whether this can actually work. Not contractors, not appointees — physicists.”

The senator warned that advancing the program without such certainty risked creating “the most expensive false sense of safety in American history,” leaving the nation unprotected in a crisis while consuming resources that could have gone toward systems with proven effectiveness.

For supporters of Golden Dome, the program represents a chance to leap ahead of rapidly advancing adversaries who have developed maneuverable hypersonic weapons and sophisticated penetration aids. For skeptics like Mr. Kelly, it raises deeper questions about the country’s approach to national security: whether political momentum is overwhelming scientific restraint, and whether the United States is repeating a cycle of investing in expansive missile shield concepts that ultimately fall short.

“Physics,” he said during the hearing, “doesn’t care what anyone in Washington believes.”

The debate appears far from over. The Pentagon is expected to release additional details on Golden Dome’s architecture later this year, and lawmakers in both parties have indicated they will seek further briefings from independent scientists and testing officials. But Tuesday’s hearing made clear that the project faces significant scientific and political obstacles — and that some of the toughest questions are only beginning to surface.