SHARE
With President Trump’s plan to create a missile defence shield for the United States and the nuclear conflict movie House of Dynamite where missile defence fails – the debate around whether reliable and effective defence from missile attack is possible is back.
In the 1980s, President Reagan’s Strategic Defense Initiative – dubbed the “Star Wars Program” by sceptics – did not produce a successful system. Reagan ended up turning to diplomacy with his Soviet counterpart Mikhail Gorbachev and agreed deep cuts in nuclear weapons arsenals as an alternative route to reducing the nuclear threat.
So, have 40 years of technological advancement made a difference to missile defence? Can a reliable missile defence system be created? Can President Trump's Golden Dome work? And what are the bigger consequences of trying to find out?
We provide answers to these questions and more.
Can a reliable missile defence system be created?
The short answer to this is probably not.
Most experts agree it would be almost impossible to develop a system that would be 100% guaranteed to destroy all incoming ballistic missiles, which, when it comes to nuclear weapons and their destructive power, is what you would need. As Xiaodon Liang, Senior Policy Analyst at the Arms Control Association, has written: “The fundamental problem with any plan for a national missile defense system against strategic nuclear attack is that cost-exchange ratios favor the offense and U.S. adversaries can always choose to build up or diversify their strategic forces to overwhelm a potential shield. The fantasy of a missile shield runs against a core rule of strategic competition: the enemy always gets a vote.”
The technical problems to be overcome are complex and varied. The existing US missile defence system, as portrayed in House of Dynamite, uses ground-launched interceptor missiles that are designed to collide with ballistic missiles and destroy them in flight. In tests that have been carried out under controlled, predictable conditions these have only worked 55% of the time as a report by the American Physical Society revealed in a report published this year.
The other major problem with trying to build a defence system against nuclear missiles is that it is likely to accelerate the new nuclear arms race that is already underway as potential adversaries increase the size of their arsenals and develop new ways to evade defences.
President Reagan’s Strategic Defense Initiative lost impetus in the 1980s and was scaled back, not just because the technical challenges could not be overcome, but also because it led to the Soviet Union producing more nuclear weapons and was an obstacle to arms control negotiations, which, in the event, did produce large cuts in the size of both US and Soviet arsenals.
How much would “Golden Dome” cost?
President Trump seems to have been impressed by the relative success of Israel’s “Iron Dome” missile defence system against short- and medium- range missiles, so he has ordered a missile defence system covering the continental US to be built that, characteristically, he has named “Golden Dome”.
The initial funding for this is $151 billion, while President Trump has claimed it will cost $175 billion and be operational by the end of his term of office in January 2029. But experts doubt both these claims and believe it will cost more. According to Todd Harrison of the American Enterprise Institute, the cost over the next 20 years could be anything between $200 billion and $3.6 trillion, depending on which threats it is designed to counter and the range it would cover, neither of which have yet been determined.
Given the widespread scepticism among experts that a 100% reliable system can ever be built, this is seen by many as a huge waste of resources that could be put to better use elsewhere.
40 years after the Strategic Defense Initiative, SDI, doesn’t new technology make it easier to defend against missile attack?
Not really because as technology that could go into missile defences has advanced, so has the technology that potential adversaries can use in their weapons. For instance, Russia and China have been developing hypersonic missiles that can change course in flight, as opposed to ballistic missiles that fly on a predictable course to their target, making interception even more difficult.
The development and integration of artificial intelligence is likely to benefit both defensive and offensive systems and not provide a decisive advantage for either.
It is also less expensive to make improvements to offensive systems than defensive ones, as this report explains, and what experts call the cost-exchange ratio, making the pursuit of a missile shield a fool’s errand in many people’s view.
What is the harm in trying to build an effective missile defence shield?
This resurgence in efforts to construct what most experts believe cannot be guaranteed to work is not just ineffective as protection from nuclear weapons, but actually counter-productive towards that goal.
The history of missile defence against ballistic missiles demonstrates that investments in trying to develop these systems have fuelled arms racing by spurring the construction of new types of nuclear weapons systems designed to avoid those defences. This competition increases the likelihood nuclear weapons will be used and on a large scale, so trying to create missile defences actually increases the threat rather than removing it.
What would happen if nuclear weapons were used again?
As long as nuclear weapons exist, so does the threat of their use. Ineffective missile defense initiatives are intended to make the population of nuclear-armed states feel as if they are protected from this reality, but that is simply not true. The use of any nuclear weapon - no matter its size, yield, or range - would have profound humanitarian consequences. After the detonation of what by today’s standards was a small nuclear weapon in Hiroshima, around 140,000 people died and generations later, people are still suffering from diseases caused by the radiation.
How can we best protect ourselves from the threat of nuclear war?
The only effective way to protect against nuclear attack is to get rid of all nuclear weapons.
The United Nations Treaty on the Prohibition of Nuclear Weapons that came into force in 2021 is the only international treaty to ban these weapons outright and prohibit all nuclear weapons-related activities. A majority of all countries has already signed or ratified it. Every country should join this treaty that delegitimises nuclear weapons and, if all countries became parties, would eliminate the threat from nuclear weapons completely.
Find out if your country has joined the treaty (and urge your government to do so if they have not)
To find out more
https://www.armscontrol.org/2025-03/golden-dome-gambit
https://newrepublic.com/article/201658/house-dynamite-explodes-missile-defense-myth
https://spacenews.com/golden-domes-cost-anywhere-from-billions-to-trillions-depending-on-design/