The Quiet Nuclearisation of Public Opinion: When Citizens Stop Trusting the Alliance

The traditional story of nuclear proliferation begins with a rogue state, a secretive programme, and years of sanctions. That story is still being written in several parts of the world. But a different and less-examined story is building in countries that are, by any measure, stable democracies with functioning economies and formal security alliances — countries that are not supposed to want the bomb.

The question worth asking in May 2026 is not only what drives governments toward nuclear ambitions. It is what drives publics there. And what is driving publics there is a collapse of confidence in the alliances that were supposed to make national nuclear deterrents unnecessary.

The number that should concentrate minds

A record 76 percent of South Koreans now support the development of indigenous nuclear capabilities. That figure is not the product of fringe nationalism or momentary anxiety. It has risen steadily over several years, tracking, with uncomfortable precision, the degree of uncertainty surrounding the US security commitment to the peninsula. South Korea is a democracy. Its government answers to those 76 percent. The gap between what a public demands and what a government eventually does tends, over time, to close.

South Korea is a signatory to the Non-Proliferation Treaty. It hosts US troops. It is, in the formal architecture of international security, deeply embedded in the alliance system. And still, three in four of its citizens have concluded that they cannot fully rely on that system for their survival.

This is not a South Korean problem. It is a signal.

How alliances lose the public before they lose the policy

Alliance credibility is not a document. It is not a treaty clause or a troop-level figure. It is a judgment that people make about whether, in the worst moment, someone will come. That judgment is shaped by everything from political rhetoric to troop withdrawal signals to the perceived stability of the government making the commitment.

Over the past several years, that judgment has been shaken across multiple allied publics. When an American president questions the value of NATO in open terms, European citizens take note. When the cost-sharing argument dominates alliance discourse, smaller partners begin to calculate what they are actually buying and whether the price is reliable. When a major ally's domestic politics become volatile enough that foreign partners cannot project its foreign policy two years forward, the certainty that undergirds deterrence starts to crack.

This is the environment in which European governments are now pouring unprecedented political will and financing into closing defence capability gaps. The framing in most capitals is about "strategic autonomy" or "burden-sharing." The underlying logic is simpler: if the US backing is uncertain, the gap must be filled by someone. Defence alliances appear poised to transition toward more regional initiatives — a shift that is strategically rational given current conditions, but one that comes with its own risks if it fragments rather than supplements the broader collective security architecture.

Energy-security shocks have accelerated this dynamic. The Iran conflict's shift into a phase of "blockade diplomacy" — with US pressure on Iranian ports and Iranian threats to shipping through the Strait of Hormuz — has raised the prospect of fuel shortages in Europe and supply disruptions in developing economies already stretched by the cost of essentials. Shared economic vulnerability can build solidarity, but it can also expose just how thin the practical commitments of an alliance run when the costs become concrete.

When self-help becomes the rational choice

Security scholars call it the "self-help" problem: in the absence of a credible external guarantor, states — and their citizens — reach for the tools they can control. For most of history, those tools stopped short of nuclear weapons because the barriers were high and the guarantor was reliable enough. When the guarantor becomes unreliable, the calculus shifts.

This is not a matter of aggression. South Koreans who support indigenous nuclear development are not expressing a desire to threaten neighbours. They are expressing a desire not to be defenceless if the alliance fails at a critical moment. The same logic runs, at lower intensity, through European debates about defence investment. It runs through the strategic calculations of any mid-size country that looks at its alliance commitments and finds the fine print ambiguous.

The problem is that once this logic spreads far enough, it becomes self-reinforcing. If South Korea develops nuclear weapons, the regional calculus shifts for Japan, for Taiwan, for every state within reach of North Korean or Chinese capabilities. If European states build up independent nuclear-relevant capabilities outside NATO's integrated structure, the coherence of that structure weakens further. Proliferation, even when driven by defensive logic, creates new instabilities that generate new demands for self-help. The spiral is not inevitable, but it is well-documented.

Against this backdrop, the scheduled meeting between US President Donald Trump and Chinese President Xi Jinping in Beijing — the first visit to China by a US president since November 2017 — carries weight beyond the bilateral agenda. How major powers signal their intentions to each other, and whether those signals include credible commitments on regional security, shapes the environment in which allied publics form their judgments. A summit that produces visible frameworks for managing competition could ease some of the pressure. One that produces theatrics without substance will not.

The non-proliferation strategy that is not being named

There is a tendency in official discourse to treat non-proliferation as a technical and legal matter — inspections, treaties, export controls, sanctions. These tools are necessary. But they operate downstream of public opinion, and public opinion is moving in directions that no inspection regime addresses.

The actual non-proliferation strategy for this decade is alliance credibility. It is making the guarantee visible, consistent, and politically durable. It is burden-sharing that is real — not a rhetorical device for extracting higher defence budgets, but a structural arrangement in which allies genuinely share risk and capability such that no single government's political volatility can pull the rug from under the whole system.

This means alliance reform, not just alliance maintenance. Integrated command structures, joint capability development, transparent commitment schedules, and — critically — the political work of explaining to allied publics why collective security serves their interests better than national weapons programmes. That last task is unglamorous. It does not generate headlines the way a new weapons system does. But it is the work that keeps the 76 percent from becoming 86 percent, and that keeps the policy debate in Seoul from following the polling.

It also means taking seriously the security concerns that drive the polling in the first place. A country whose public has reached 76 percent support for nuclear weapons is telling the alliance something. The productive response is not to lecture on treaty obligations — it is to ask what, concretely, has eroded the confidence that made those obligations feel sufficient, and to address that erosion directly.

What credible assurance looks like

Trust in collective security is rebuilt the same way any institutional trust is rebuilt: through demonstrated reliability over time, not through assertions of commitment. For the US and its partners, that means visible and consistent follow-through on security commitments even when domestic political pressures push in other directions. It means alliance structures that distribute decision-making and capability widely enough that no single election outcome can unravel them.

For European partners, it means taking on genuine capability and not merely spending targets — building the kind of integrated capacity that makes the alliance's collective deterrent credible to citizens in Warsaw and Seoul alike, not just to planners in Brussels.

For all parties, it means treating the public as a participant in the security conversation, not merely a constituency to be managed. When governments fail to explain why alliances work and what sustains them, publics fill the gap with simpler calculations. Simpler calculations tend to end at self-reliance. And the most extreme form of self-reliance, in the security context, has a half-life that compounds.

The proliferation risk of this decade will not be resolved purely by arms control. It will be resolved — or it will not — by whether the governments that built the postwar security order can demonstrate, plainly enough for a citizen in Seoul or Stockholm to see, that collective security is not a slogan. It is a working system, worth keeping.

The Global Federation World Affairs Desk covers governance, security, and international order through the lens of what works for people — not just states.

Sources: