海角大神

Everyone agrees that President Donald Trump鈥檚 proposed massive missile defense system 鈥� nicknamed the 鈥淕olden Dome鈥� 鈥� will carry huge costs. The question for policymakers is whether the system serves as a necessary safeguard for America, or a destabilizing force in the world鈥檚 complex global nuclear arms balance.

It鈥檚 a question that hinges on whether any current defense strategy can effectively counter the fast-emerging class of modern weaponry.

Both Republicans and Democrats support updating America鈥檚 missile defenses. But low-tech surprise attacks like the one Ukraine launched against Russia this week 鈥� using inexpensive drones hidden in modest wooden huts with retractable roofs 鈥� have complicated the debate.

What鈥檚 a Golden Dome?

There remains some basic uncertainty about what precisely a Golden Dome is, even among specialists who describe it as a sprawling 鈥渟ystem of systems鈥� involving everything from space-based interceptors to dirigibles closer to Earth.

The combination of multilayered space and land-based weapons is designed to provide a protective shield over the country by detecting and intercepting standard or nuclear missiles during flight, and potentially even before they are launched.

The name is a nod to Israel鈥檚 Iron Dome, which has been largely successful in defending against low-tech rocket barrages. Mr. Trump originally referred to his proposal as an 鈥淚ron Dome for America鈥�; however, 鈥淚ron Dome鈥� is a trademark owned by an Israeli defense corporation.

The 鈥渄ome鈥� idea harkens back to America鈥檚 1983 Strategic Defense Initiative 鈥� known as 鈥淪tar Wars鈥� 鈥� that aimed to protect the U.S. 鈥渇rom nuclear missiles just as a roof protects a family from rain,鈥� as then-President Ronald Reagan put it. That program was shut down a decade later amid technological challenges as the Cold War drew to a close.

Today, President Trump says that his goal, using improved technological advances, is 鈥渃ompleting the job that President Reagan started鈥� and, in so doing, 鈥渇orever ending the missile threat to the American homeland.鈥�

Mr. Trump estimates that the Golden Dome will take three years to complete, cost about $175 billion, and be 鈥渧ery close to 100%鈥� effective. On each of these points, experts express skepticism.

How would it work?

The Golden Dome would defend against cruise missiles, which fly low, rendering them tough to track by standard radar, says Bradley Bowman, senior director of the Air and Missile Defense Program at the Foundation for Defense of Democracies.

It could also protect against hypersonic glide vehicles. Launched by ballistic missiles into the Earth鈥檚 upper atmosphere, these glide weapons detach and move toward targets at hypersonic speeds, changing course and turning wildly 鈥� maneuverability that defies conventional algorithms for projecting flight paths.

To defend against these weapons, some experts say, it鈥檚 necessary to place a 鈥渄ome鈥� of sensors and weapons in space, thus the Golden Dome moniker. 鈥淵ou have to get your radars up high, looking down for missiles coming in at different altitudes and different speeds,鈥� Mr. Bowman says.

Scaling such a defense system is a challenge.

While Israel鈥檚 Iron Dome defends a nation the size of New Jersey, the U.S. would need to put some 10,000 weapons in space, for example, to counter less than a dozen North Korean intercontinental ballistic missiles (ICBMs) launched at the same time.

Current U.S. missile defense systems, chiefly focused on shooting down rogue missiles from North Korea or Iran, 鈥渁re designed for a very narrow purpose, one or two missiles,鈥� says James Brown, a political science professor at Temple University, Japan Campus.

However, even as many arms control advocates support parts of the Golden Dome plan, concerns persist over its sprawling, still-undefined scope.

鈥淚f resources are endless, then you could perhaps justify this,鈥欌�� says Mr. Brown of Temple University. 鈥淏ut given how much it鈥檚 likely to cost, surely there are other things that would be more deserving of these hundreds of billions of dollars.鈥�

What would the Golden Dome cost?

A recent Congressional Budget Office report says that though top estimates for building such a program have decreased by a third 鈥� from $831 billion to about $542 billion 鈥� over the past 20 years, due mainly to lower space-launch expenses 鈥� threats have simultaneously grown 鈥渋n ways that could increase the overall size and cost鈥� of a Star Wars-style defense system. Costs could also be higher due to increased sophistication and the number of ICBMs from potential adversaries, such as North Korea.

The Golden Dome system, which Mr. Trump says will cost $175 billion 鈥� a figure at the lowest end of the CBO estimate 鈥� has already been allocated $25 billion. That鈥檚 2.5% of the total Defense Department budget鈥檚 $1 trillion request this year 鈥� for its initial phase. But final costs are unclear, as the initiative is currently in the conceptual stage.

As such, the proposed project is seen by many defense analysts, in Pentagon parlance, as an 鈥渆xquisite鈥� system 鈥� a term used to imply doubts about a weapon鈥檚 technological feasibility and cost-effectiveness.

Sen. Jack Reed, the top Democrat on the Senate Armed Services Committee, has called it 鈥渆ssentially a slush fund.鈥�

Even supporters are quick to concede how costs are often low-balled. 鈥淚鈥檓 34 years in this business,鈥� Gen. Chance Saltzman, commander of U.S. Space Force, said at a Politico event last month. 鈥淚鈥檝e never seen an early estimate that was too high.鈥�

The Golden Dome project would also require defense budget tradeoffs, most notably around the size of the U.S. Army, including troop strength. Defense Secretary Pete Hegseth warned in an April memo that the Army must 鈥渟treamline its force structure鈥� to prioritize air and missile defense through the Golden Dome.

The technology, too, isn鈥檛 fully developed. 鈥淵ou don鈥檛 buy Golden Dome. You orchestrate a program that includes a lot of programs that you stick together in very technical ways,鈥� General Saltzman said.

The prospect of building and maintaining a Golden Dome indeed remains a 鈥渄aunting challenge,鈥� according to an American Physical Society Panel on Public Affairs report, published in February.

But most agree that the United States needs to improve its missile defense.

A Golden Dome 鈥渋s going to be much more costly and time-consuming than people realize. It鈥檚 incredibly ambitious,鈥� says Mr. Bradley Bowman, senior director of the Air and Missile Defense Program at the Foundation for the Defense of Democracies. 鈥淚t鈥檚 also absolutely necessary.鈥�

Would it make the world safer?

Despite the risks defense budget cuts pose, President Trump鈥檚 impulse to build a protective shield for America is understandable, Professor Brown says.

鈥淔or all of his faults, he doesn鈥檛 seem to be a warmonger. I think he鈥檚 been taken by this quite simple idea that if missile defense works, then it could be the route to reducing nuclear weapons stockpiles,鈥� he adds. 鈥淚f you鈥檝e got a good defense, you don鈥檛 need so much of an offense.鈥�

The problem, Professor Brown and others say, is the view from the other side. America鈥檚 rivals see this defense as a mounting offense.

鈥淎nother way to imagine this as an American is that if tomorrow we woke up and read in the papers that [Chinese leader] Xi Jinping had just authorized a Golden Dome for China that would render the U.S.鈥檚 ability to hit China with nuclear weapons moot,鈥� Mr. Panda says. 鈥淭he U.S. would not see that as a defensive measure being taken by China.鈥�

Indeed, Chinese foreign ministry spokesperson Mao Ning told reporters last month that the plan 鈥渉eightens the risk of space becoming a battlefield.鈥�

In this way, the Golden Dome could serve 鈥渒indling for a three-way arms race鈥� between China, Russia, and the United States, Mr. Panda says, even as Russian President Vladimir Putin steps up development of what he calls nuclear 鈥渟uper weapons.鈥欌�櫬�

Such developments are 鈥渃ompletely at odds鈥� with President Trump鈥檚 statements that he is trying to decrease the risk of nuclear war, Professor Brown says.

鈥淢y hope is that the White House will follow the president鈥檚 instincts on denuclearization,鈥� Mr. Panda says, 鈥渁nd actually find ways to mitigate an arms race.鈥�