Is Trump's Golden Dome a Brilliant Idea or a Gilded Boondoggle?

Days after taking office for a second time, President Trump issued an executive order for a homeland missile defense system, dubbed Iron Dome for America. Unlike Israel’s Iron Dome, which defends against short-range threats, this system would defend a much larger area against a more challenging range of threats, including intercontinental ballistic missiles (ICBMs) and hypersonic weapons.

The Golden Dome Trump envisions is most similar to the Strategic Defense Initiative (SDI) proposed by President Ronald Reagan in the 1980s. What has changed in the past four decades, however, is the technical feasibility, strategic calculus, and politics of homeland missile defense, each of which is important for understanding whether Trump’s Golden Dome is a smart strategic move or a wasteful diversion of defense resources.

Golden Dome’s sensing and command and control functions are complex but entirely feasible. Many of the sensors and communications systems Golden Dome will use will be in space, since satellites allow the military to see and communicate over longer distances and without regard to national borders. Advances in commercially available technology have made satellites smaller, cheaper, and more capable than ever before, and the Space Force is beginning to leverage commercial space technology in its next-generation satellite constellations.

Intercepting missiles in flight is the most technically challenging part of Golden Dome—like trying to hit a bullet with a bullet—but even this is more feasible now than ever. The Ground-based Midcourse Defense (GMD) system faced numerous setbacks throughout its development, but the system is now operational with 44 missiles deployed in total between Alaska and California. Other interceptors, such as Patriot, THAAD, and SM-3s, may also play a role in Golden Dome, providing additional layers of protection for different types of air and missile threats. However, Golden Dome will require many more interceptors than the US military currently has or is planning to buy. These programs will need to increase production rapidly to meet the timelines the Trump administration has in mind.

The most notable new program called for in the Golden Dome executive order is a space-based interceptor system composed of satellites that can shoot down missiles during the boost-phase of flight. A system like this, known as Brilliant Pebbles, was part of SDI in the 1990s. The idea resurfaced during the George W. Bush administration and again in the first Trump administration. Space-based interceptors never made much progress in the past.

While the technology required for space-based interceptors was arguably immature in the 1980s and 1990s, that is not the case today. The missile tracking and homing technology that developed and matured as part of the GMD program is directly applicable to space-based interceptors. Moreover, the ability to deploy and operate a large constellation of satellites like that required for a space-based interceptor system is now commonplace for commercial space operators, and the cost of launching a large constellation has declined significantly.

As I discussed in a recent article, the issue with space-based interceptors is not the technology; it’s how it scales with the threat. The physics of space-based interceptors mean that they inherently have an absenteeism problem—each interceptor spends the vast majority of its time each orbit out of range of any missiles it could intercept. According to my calculations and using fairly generous assumptions for the performance of each interceptor, it takes about 950 interceptors spread out in orbit around the Earth to ensure that at least one is always in range to intercept a missile during its boost phase. If an adversary launches ten missiles in a salvo, it requires some 9,500 interceptors in space to ensure at least ten are within range to intercept all of the incoming missiles.

Given that China has about 350 ICBMs and Russia has 306, not including their sub-launched ballistic missiles, scaling a space-based interceptor system to meet the threat quickly becomes impractical. In peacetime competition, this means an adversary can build missiles faster and more affordably than we can build the space-based interceptors needed to counter them. Even senior defense officials from the first Trump administration that previously supported the concept have now concluded, “It is not worth spending your money on a space interceptor constellation that is targeting the boost phase.”

No matter how many different layers are included in Golden Dome, whether space-based or not, homeland missile defense will never be iron clad. Policymakers should limit their expectations for what can be deployed by the end of 2030. The objective should be a system that can reliably defeat an attack by North Korea or Iran and merely blunt a large-scale attack by China or Russia. This much is technically feasible, but it will require substantial and sustained funding on the order of tens of billions of dollars over the next decade and beyond.

The main strategic argument against homeland missile defense in the past was that it would lead to an arms race and strategic instability. This line of reasoning argues that an effective missile defense system could cause an adversary to believe their nuclear arsenal is less effective, leading them to pull out of arms control agreements and rapidly expand their missile forces to compensate. In the worst-case scenario, an adversary could conclude that if the United States builds its missile shield, their nuclear forces would no longer be sufficient to deter an American first strike—putting them in a use-it-or-lose-it situation that could lead them to conduct a preemptive nuclear attack against the United States.

These arguments are largely based in a Cold War mindset, when the United States faced a single peer adversary with somewhat symmetrical capabilities that was bound by arms control agreements. Today, the United States faces two near-peer adversaries (Russia and China) that pose very different threats, and two rogue nations (Iran and North Korea) with the capability and/or ambition to hold the US homeland at risk. Unlike the Cold War, Russia is by many measures a declining power with revanchist ambitions, and China is a rising power rapidly expanding its nuclear and conventional missile forces unconstrained by arms control agreements. While China is already in an arms race against the United States, the United States is limited by the New Start treaty with Russia.

Worries that a homeland missile defense system like Golden Dome would be destabilizing in the current strategic environment are rooted in the mistaken idea that such a shield would be perfectly effective, but no missile defense will ever be that good. Golden Dome would not give the United States a free pass to attack other nuclear-armed nations because if it did, at least some part of their retaliatory attack would still be effective. Even if only one or two adversary warheads made it through, it is a risk the United States would not be willing to take unless it was already under attack.

On the contrary, real-world experience has shown that effective missile defense can be stabilizing because it gives political leaders decision space—more time and options to develop a response. Iranian missile attacks against Israel in recent months have demonstrated this. In April 2024, Iran launched a salvo attack of more than 300 drones and missiles at Israel, and in October 2024, it launched another attack using 180 ballistic missiles. In both cases, Israel’s layered missile defense systems gave political leaders space to formulate an effective response in the time and manner of their choosing. Had the damage in Israel been more severe, especially against civilian areas or critical military capabilities, the political pressure for rash escalation could have pushed the region into a much broader and costly conflict. The same is true for US forces in the Red Sea defending against missile and drone attacks by Houthi rebels in Yemen—if Houthi missiles successfully hit even a fraction of the ships they targeted, the United States would have no choice but to escalate swiftly and severely.

Perhaps the most important strategic consideration is how the pending deployment of Golden Dome would affect potential arms control negotiations with Russia and China. Unlike many of President Trump’s policies, homeland missile defense is something Russia hates and views as a direct threat to its sovereignty. China has also expressed deep concerns about US missile defense, in part because it undermines the buildup of its nuclear forces currently underway. Days after Trump signed the Golden Dome executive order, he indicated a desire for arms control negotiations with both Russia and China, saying, “One of the first meetings I want to have is with President Xi of China, President Putin of Russia. And I want to say, ‘Let’s cut our military budget in half.’ And we can do that. And I think we’ll be able to.” Golden Dome could raise the incentive for both countries to engage in multilateral arms control negotiations in hopes that limits on Golden Dome will be part of the deal.

While the Trump administration and its Republican majorities in both the House and Senate can kickstart the effort, building something this complex will require bipartisan support well beyond the term of this administration. Democrats have historically favored regional missile defense over homeland missile defense, but in more recent years that sentiment has begun to shift. A complicating political factor, however, is the overall budget outlook and deficit projections. Barring a significant and sustained increase in defense spending, Golden Dome will be forced to compete for funding with other national security priorities, including nuclear modernization and shipbuilding.

The greatest risk for Golden Dome, however, can be seen in the name itself. It is highly unusual to name a major new weapon system after the gilded proclivities of the commander in chief who proposed it. Linking a homeland missile defense system to a divisive political persona raises the prospect of partisan backlash. It may prove difficult if not impossible for Trump’s political opponents to support something so closely linked to his personal brand and image.

Golden Dome is technically feasible and strategically sound overall, with the notable exception of space-based interceptors, which the laws of physics continue to render impractical. The main mark against Golden Dome is the political risk that a future Congress or new administration will terminate it—a risk the Trump administration exacerbated by naming the system Golden Dome. The US military could spend billions of dollars developing it only to have a subsequent administration kill the effort before it bears fruit. Golden Dome could become the poster child for waste and inefficiency in defense.

None of this may matter, however, if the real objective of the program extends beyond missile defense. Just as President Reagan used the existence of the SDI program for negotiating leverage with the Soviet Union, President Trump may have a similar strategy in mind for Golden Dome. Importantly, Reagan did not use SDI as trade bait in exchange for arms control. Instead, he offered to share missile defense technology with the Soviets and steadfastly refused to end SDI. Since taking office for a second term, President Trump has repeated his desire for multilateral arms control negotiations that include both Russia and China. It is not yet clear what Trump’s strategy may be for arms control talks, but his stated desire for deep reductions in defense spending suggests Golden Dome may be more trade bait than serious policy.