The global nuclear order, traditionally anchored in treaties such as the Nuclear Non-Proliferation Treaty (NPT) and Comprehensive Nuclear-Test-Ban Treaty (CTBT) alongside norms like the nuclear taboo, is weakening. The NPT once functioned as the historic foundation, credited with major achievements such as reducing nuclear arsenals by 90% and enabling international verification regimes. Today, it shows significant decline. Participation is thinning, deliverables like the P5 process have stalled, and proliferation pressures are rising. The possibility of withdrawals (whether by Ukraine, Iran, or others) threatens to hollow the treaty into a “zombie” framework, existing in name but no longer constraining states. In this environment, European security cannot assume the NPT will provide the same level of stability it once did.
Against this backdrop, the European nuclear order stands out for its reliance on collective security and extended deterrence. These features are now under strain. The erosion of the principle of territorial integrity (challenged most visibly by Russia’s war against Ukraine) strikes at the foundation of the European security order established since Westphalia. International politics are becoming more competitive and transactional, and this is filtering down into nuclear politics. For Europe, this means deterrence and reassurance are once again central, while disarmament and arms control have lost traction. Nuclear deterrence, once viewed sceptically in some European publics, is now seen as unavoidable, even as debates about risk reduction and responsibility continue.
Several elements of the nuclear order are particularly consequential for Europe’s security:
- The credibility of extended deterrence and alliance commitments. Russia’s regular nuclear threats, combined with its growing investment in unconventional and hybrid capabilities, underscore the importance of keeping deterrence credible in practice and visible in signalling.
- Non-proliferation challenges. A more proliferated world, especially if the NPT collapses, would make Europe less safe and could trigger destabilising cascades across WMD domains.
- The preservation of knowledge and expertise. The risk of generational knowledge loss in arms control, verification, and deterrence practices, could weaken Europe’s ability to manage crises or negotiate future frameworks.
In terms of safeguarding the regional nuclear order, allies need to adopt a posture of adaptation rather than conservation. The goal should not be to preserve the old order at all costs, but to prepare for a possible transformation. Deterrence needs safeguarding, with nuclear alliances at the core. Non-nuclear allies can contribute by countering Russian and Chinese disinformation, strengthening public awareness about adversaries’ nuclear activities, and engaging actively in strategic communications. The UK and France also have a role to play in the P5 Process, where it can push ambitious risk-reduction agendas and call out the obstructionism of Russia and China. Finally, cooperation across the non-proliferation, disarmament, and deterrence communities will be essential, ensuring a shared understanding of challenges rather than siloed debates.
Europe cannot afford passivity. The nuclear order is dynamic, not static, and at a possible inflection point. If the NPT weakens further and U.S. leadership recedes, Europe will face a harder security environment where deterrence, non-proliferation, and public reassurance become indispensable pillars of stability.