Trump’s Golden Dome Is a Fantasy. Canada Could Still Be Dragged into It

Total protection against nuclear attack is impossible. But saying no won’t be easy

IN JULY OF 1979, Ronald Reagan, then eighteen months from the presidency, was taken to see the North American Aerospace Defense Command, better known as NORAD. The underground facility, jointly run by the United States and Canada, is carved inside Cheyenne Mountain, near Colorado Springs. In one widely cited account of the visit, many on the tour were visibly awed by the scale and seriousness of the operation. But when Reagan asked what the US could do to stop a nuclear missile, the answer shocked him: nothing.

As the story goes, Reagan was told that all NORAD could do was track incoming warheads and provide information for retaliation. During the flight home, one aide remembered, Reagan “couldn’t believe the United States had no defense against Soviet attack. He slowly shook his head and said, ‘We have spent all that money and have all that equipment, and there is nothing we can do to prevent a nuclear missile from hitting us.’”

Reagan agonized over the idea of the US being vulnerable. “We should have some way of defending ourselves,” he concluded. His vision eventually took the form of the Strategic Defense Initiative: a plan for futuristic weapons in space—lasers, interceptors, armed satellites—that would render nuclear missiles “impotent and obsolete.” SDI was a promise as sweeping as it was speculative, and it ultimately petered out under the weight of its technical limits and astronomical costs.

After Reagan left office, his successors, George H. W. Bush and Bill Clinton, quietly but significantly pared back SDI, largely shelving the space-based part and concentrating on land-based interceptor missiles that could meet a much more limited threat. About two decades later, George W. Bush went forward with this version of the idea. His system was designed to defeat not thousands or even hundreds of weapons launched by a peer adversary but to stop a handful of missiles from a so-called rogue state. Though something workable was produced, it, too, fell short of ambitions (only about half of its highly scripted test interceptions have worked).

Now Donald Trump has unveiled his own iteration of Reagan’s old aspiration: the Golden Dome. He claims it will cost $175 billion (US), be completed by the end of his term, be 100 percent successful, and thus be capable of “forever ending the missile threat to the American homeland.” The plan has notable supporters, mainly Republicans, defence hawks, and industry players. Few credible experts believe the hype. The American Enterprise Institute, a conservative think tank, estimates the cost could rise to more than $3 trillion (US) and the system could take decades to build—if it can ever succeed.

Trump has asked Canada to join. He has spoken of between $61 billion and $71 billion (US) as the Canadian contribution—though he has generously offered it to us for free for the mere price of our sovereignty. The previous times missile defence arose, under Reagan and Bush, Canada was also invited. We said no—sort of—and life went on. However, in Trump’s fantasy of the Golden Dome, he wants Canada to commit during his term. Though there were hints of repercussions for refusing to join the Reagan and Bush projects, they never amounted to much. Trump’s assault on our economy makes the possibility of reprisals more serious.

But the key difference between today’s project and the Reagan and Bush invitations is that missile defence itself is no longer a hypothetical. A limited—if leaky—missile defence does now exist, built in Alaska at great cost since the George W. Bush presidency. Although we formally declined to participate, Canada is embedded in its architecture. NORAD operates many of the sensors and networks that support the system. And with significant upgrades to NORAD now underway, even as Canada insists no decision has been made on the Golden Dome, the real question is not whether Canada will participate—but on what terms and to what end.

SINCE THE DAWN of the nuclear age, strategists have searched for ways to defend against catastrophic attack. The advent of intercontinental ballistic missiles (ICBM) in the 1950s exposed the limits of that goal. In practical terms, there is no reliable way to shoot them down. It requires striking targets moving at extraordinary speed, in the near vacuum of space, across thousands of kilometres—what missile-defence engineers call “hitting a bullet with a bullet.”

By the late 1960s, many in the defence establishment had concluded the price of security was accepting mutual vulnerability rather than chasing the illusion of perfect protection. This came to be known as Mutually Assured Destruction (MAD), a doctrine enshrined in two key arms control agreements between the US and the Soviet Union in 1972: the Strategic Arms Limitation Treaty (SALT) and the Anti-Ballistic Missile (ABM) Treaty. Together, they sought to make nuclear war untenable by preserving what strategists call an “assured second-strike capability.” Each side would retain the ability to retaliate after a surprise attack, guaranteeing that any country irrational enough to launch a first strike would be obliterated by the retaliatory—or second—strike.

SALT drew most of the attention. It channelled the buildup of arsenals in ways that ensured neither superpower believed it could escape annihilation. The ABM Treaty flowed directly from this reasoning, placing strict limits on missile-defence systems. The thinking was that if you believed you could erect a shield that could stop at least some incoming warheads, the temptation to launch a first strike would grow; you hit early, wipe out most of your opponent’s forces, then rely on your defences to blunt the weakened response. Leaving aside the reality that a first strike would still be madness, as no missile-defence system could ever be fully trusted to deal with the retaliation, the tactic had a certain grim logic. The only answer was to remove the incentive entirely and turn away from the notion that nuclear war could be anything other than a suicide pact.

Not everyone accepted MAD. Some argued it was wrong to foreclose the possibility of ballistic missile defence (BMD). In their view, the assumption of shared extinction condemned the US to accept the existence of the Soviet Union. Even worse, it established equivalence between the two—they would be equally vulnerable. On a political, ideological, and indeed a moral level, the idea that America’s existence required the acquiescence of the godless Soviets deeply offended some people.

By the late 1970s, opponents of the SALT and ABM treaties, and of détente more broadly, controlled the Republican Party, with Reagan as their leader. It did not matter that BMD was impossible. What mattered was that the US should not accept MAD, or any limitations on the effort to overcome it. Reagan’s missile defence was an attempt to will an alternative to MAD into being. As Frances FitzGerald notes in Way Out There in the Blue, her sweeping account of missile defence under Reagan, the pursuit proved “the extent to which our national discourse about foreign and defense policy is not about reality—or the best intelligence estimates about it—but instead a matter of domestic politics, history, and mythology.”

The basic problem for BMD is that physics is stubbornly resistant to ideology. It takes approximately thirty minutes to send an ICBM around the world. A missile shield must respond instantly, distinguish real warheads from decoys, track them as they travel at thousands of kilometres per hour, and guide interceptor missiles—or, in more futuristic schemes, laser beams—to them. It has to be at peak readiness at all times and work perfectly on first use. No complex system has ever achieved this, but this is the standard because of the stakes. Stopping 90 percent of warheads is not enough. McGeorge Bundy, national security adviser to presidents John F. Kennedy and Lyndon B. Johnson, warned that even ten bombs landing on heavily populated centres would be a “disaster beyond history.” BMD must be flawless.

Nor does missile defence make sense if it can be overcome more cheaply than it can be built. Paul Nitze, a central figure in US nuclear policy and arms control, concluded in 1985 that any shield must be “cost effective at the margin.” If it costs far more to intercept a missile than to manufacture one, an adversary can simply overwhelm the defence by adding more missiles. Cheaper still are decoys—dummy warheads designed to force the enemy’s system to fire interceptors uselessly, thereby allowing real warheads to slip through. The result is an arms race tilted in favour of the attacker, who can force the defender to spend endlessly just to keep pace.

Missile defence may never be “cost effective at the margin” until so-called directed-energy weapons, such as lasers and particle beams, can reliably intercept missiles. Such systems would be based in orbit in order to attack the ICBMs as they rise out of the atmosphere in the initial stages of their flight, the so-called boost phase. They would be able to take unlimited shots, provided the energy source is unlimited, and the “cost per shot” would be negligible—though the upfront cost of building the infrastructure would be enormous. The technology shows promise, but as a defence against missiles aimed at cities, space-based lasers are decades from deployment, if they can ever be perfected.

Finally, even if cost-effective BMD were possible, adversaries would not accept it. They would move to defeat it. They would grow their stockpiles and develop missiles with unconventional trajectories, more sophisticated cruise missiles, or ways of clandestinely smuggling nuclear weapons onto enemy territory. A missile shield that renders an adversary’s nuclear arsenal useless won’t be seen by the other side as defence but as an act of aggression. It eliminates their deterrent, leaving them exposed. As Ankit Panda, a nuclear policy analyst, put it in an interview with The Christian Science Monitor, “if tomorrow we woke up and read in the papers that Xi Jinping had just authorized a Golden Dome for China that would render the US’s ability to hit China with nuclear weapons moot, the US would not see that as a defensive measure being taken by China.”

An impervious Golden Dome, as Trump imagines it—absolute protection against all doomsday missiles, including cruise and hypersonic ones—would drive the nuclear arms race in new, dangerous directions.

WILL IT EVEN WORK? Beyond bold claims, details remain vague. What has been described publicly amounts to a concept rather than a plan: a layered system combining an expanded version of the existing Bush-era land-based interceptors with new sensors and weapons in space. The promise is total: detect every launch, track every warhead, and stop them all before they land.

But no architecture of any detail has been released, and, again, there is scant evidence the underlying technologies—the space-based lasers especially—are close to serious testing, let alone ready to deploy. Key questions about costs remain unanswered. The proposal resembles Reagan’s earlier missile-defence vision: extravagant in scope, light on specifics, and dependent on breakthroughs that have eluded scientists and engineers for decades.

Golden Dome proponents say they can get there. They point to Israel’s Iron Dome as proof that missile defence can work in practice. The Iron Dome emerged from Israel’s experience with sustained bombardment, particularly from Hezbollah in southern Lebanon and later Hamas in Gaza. After the 2006 Lebanon War exposed Israel’s vulnerability to inexpensive, unguided rockets, the government accelerated the development of a defensive system tailored to that specific threat. Built with US financial and technical support, the Iron Dome became operational in 2011. It has successfully intercepted thousands of incoming projectiles fired at Israel under real combat conditions. Supporters argue that this shows the technology can blunt missile threats and that similar principles could be adapted to protect a country like the US.

But the comparison is misleading. The Iron Dome isn’t optimized for intercontinental or hypersonic warheads. It works precisely because the threat it faces is far slower and simpler. As Ukraine’s then defence minister explained in 2022 when asked why the country did not buy the Iron Dome, he said the system was made to protect against artillery “basically made in garages,” not the sort of weapons Russia is firing at Ukraine.

Moreover, the Iron Dome has a success rate of around 90 percent, and it does not engage incoming fire it assesses as likely to land in an unimportant area. So it is more accurate to say that it is 90 percent effective in cases where it engages. This is impressive, but it still allows 10 percent of missiles fired at population centres to get through, as well as an unknown number of missiles fired at areas the system regards as of lesser importance.

So, to the question “Why can’t we just scale the Iron Dome up to defend North America?” the answer is that defending an area the size of New Jersey from a few pounds of airborne explosives is not the same as safeguarding an entire continent from nuclear-tipped ICBMs. And even for a small-scale defence, Nitze’s “cost effective at the margin” formula still lies with the offence. On October 7, 2023, Hamas fired an enormous number of rockets at Israel, and many got through. According to recent estimates, an Iron Dome interceptor costs between $40,000 and $50,000 (US), while Hamas can manufacture crude salvos for about $600 (US). The Iron Dome has an important psychological effect: the sense of security it gives Israelis allows their political leaders to take risks they might not otherwise. But it cannot defeat thousands of sophisticated warheads and decoys aimed at an exponentially larger geographic area.

Proponents next point to the fact that Israel has already begun to test a laser supplement to the Iron Dome. Dubbed the Iron Beam, the system has successfully shot down rockets, mortars, and drones. But these experiments happened in highly controlled settings. Even there, the obstacles are significant. Lasers are easily degraded by atmospheric conditions, such as clouds, dust, smoke, or rain, which can scatter or absorb the beam before it reaches a target. Range is another limit. The system works best against short-range threats and small projectiles, not high-altitude or long-range missiles. So-called “dwell time” matters too: the laser must stay on a target long enough to disable it. This is a tall order against fast or unpredictably manoeuvring threats.