Making Europe's Nuclear Deterrent Fit for Purpose.

Why European nuclear powers must deploy a non-strategic nuclear deterrent.

Picture: French Ministry of Defense

In recent weeks, it has truly felt as though Europe is at a crossroads, and not only due to the U.S. election on Tuesday. Across the board, key Western officials, particularly in North America and Western Europe, are failing to take the necessary steps to avert a catastrophe in Ukraine.

While I still believe that the West has every tool needed to decisively defeat Russia in Ukraine and prevent a large-scale Russian threat to Europe, the lack of political resolve in major capitals remains a serious concern.

This raises questions about the future we are moving toward—and, more importantly, how we can prepare for it. Europe’s nuclear deterrent can and must play a central role in ensuring Europe’s security. Unfortunately, at present, this deterrent is not fit for purpose.

European shortcomings

Europe has two independent nuclear powers, France and the United Kingdom. The problem, however, is that their nuclear deterrents are structured in a way that Europe must rely on the U.S. nuclear arsenal to cover remaining and crucial capability gaps.

Currently, the French and British nuclear arsenals and doctrines are primarily deployed to deter strategic nuclear attacks through the threat of massive retaliation against enemy population centers.

Neither France nor the United Kingdom deploys low-yield nuclear warheads that offer more flexible employment options. The French nuclear arsenal includes TN-75 and TNO warheads with yields of 150 kT deployed on M51 submarine-launched ballistic missiles (SLBMs), as well as ASMP-A supersonic air-launched cruise missiles equipped with TN-81 warheads with yields of 300 kT.

The ASMP-A technically serves as a non-strategic option, intended to provide a final warning to the adversary when used against a non-strategic target (i.e., not a city) before escalating to strategic nuclear use, presumably through M51 SLBMs. However, the high yield of ASMP-A’s warhead prevents flexible use for other purposes.

The United Kingdom’s nuclear arsenal is limited to American W76 and W88 warheads, with yields ranging from 90 kT to 455 kT, deployed on Trident II D-5 SLBMs.

This means that for nuclear warfighting and escalation management, Europe relies almost entirely on the U.S. nuclear arsenal, particularly W76-2 low-yield nuclear warheads deployed on nuclear-armed submarines and scalable-yield gravity bombs, which provide flexibility across various nuclear scenarios. If the United States’ non-strategic nuclear presence were removed from Europe’s defense posture, a critical deterrence gap toward Russia would emerge.

This is particularly concerning as Russia is likely to increase its reliance on non-strategic nuclear weapons in its nuclear posture in the coming years.

At present, Russia’s strategic nuclear deterrent faces numerous challenges, including limited survivability against advanced U.S. and European nuclear and conventional capabilities, as well as issues within its modernization programs.

Fortunately for Russia, it possesses a large and diverse non-nuclear strategic arsenal to lean on. While nuclear-capable 9M723 short-range ballistic missiles and 9M729 cruise missiles, with ranges between 500 and 2,500 km, cannot reach the U.S. homeland, they pose a credible threat to several European capitals as well as critical NATO infrastructure and military targets.

What is needed

Europe needs options to deter Russian non-strategic nuclear use without relying solely on the threat of massive strategic nuclear retaliation, which, due to its consequences and the Russian counter-response it may provoke, lacks credibility at this rung of the escalation latter.

European nuclear powers, and Europe at large, require an effective non-strategic nuclear capability that can serve a range of functions, including signaling, warfighting, escalation management, and retaliation.

This calls for immediate investment by European nuclear powers, starting with France. France, which already has the necessary infrastructure, should invest rapidly in deploying a true low-yield (or ideally, scalable-yield) nuclear option for non-strategic use. Simultaneously, France should publicly announce an update to its nuclear doctrine. While France has a longstanding tradition of avoiding tactical or non-strategic nuclear deployments, changing threat scenarios and priorities warrant a doctrinal shift.

The United Kingdom, meanwhile, faces a more complex challenge, given its dependency on U.S. technology for nuclear warheads and delivery vehicles. Nonetheless, the United Kingdom must invest in re-establishing its own warhead development capacities.

Given the extent to which the credibility of the United Kingdom’s sea-based nuclear deterrent is in question due to compounding maintenance failures, it would be highly prudent to establish an air-based nuclear deterrent for its F-35 fleet. Ideally, this would include a low-yield stand-off nuclear missile capability.

Non-nuclear weapon states in Europe should also consider how they can contribute to deterring and countering Russian non-strategic nuclear use. Conventional options for targeting time-sensitive assets, such as nuclear missile launchers, should be part of this portfolio.

That said, deterring nuclear weapons with non-nuclear capabilities is extremely challenging and likely unsustainable. Therefore, the bulk of investment must come from Europe’s nuclear weapon states—primarily France. In any case, Europe’s current nuclear posture is inadequate and requires urgent adaptation.