All N5 states, with the exception of China, have adopted a policy that permits the use of nuclear weapons to deter non-nuclear strategic threats. This is defined as weapons that nuclear weapon states (NWS) believe can have catastrophic effects similar to nuclear weapons. The UK, the US, and Russia have explicitly stated their intention to deter non-nuclear strategic threats from new technologies with nuclear weapons. It can be assumed that a similar policy is in place for France, although Paris is less explicit about it. This shift is problematic for several reasons. Notably, some EDT-related threats cannot be deterred by nuclear weapons. The assumption is that they can risk leading to a sense of complacency among policymakers, discouraging them from exploring alternative means of addressing such threats. Furthermore, this policy is at odds with the NWS’ commitment in the Non-Proliferation Treaty (NPT) context to reduce the role of nuclear weapons. Moreover, it could potentially exacerbate proliferation risks if non-nuclear weapon states perceive nuclear weapons as an adequate tool to deal with any potential or hypothetical threat.

For these reasons, the NPT NWS – and all other nuclear weapons possessors – should refrain from deterring threats of non-nuclear strategic threats with nuclear weapons.

Evolution of the policy to deter new tech with nukes

From a historical perspective, nuclear deterrence of non-nuclear strategic-level attacks involving emerging technologies marks the third widening by NWS of the purpose of nuclear weapons. During the first phase of nuclear weapons, which lasted up until the 1980s, NWS saw deterrence of large-scale conventional and strategic-level nuclear attack as the main purpose of nuclear weapons. In the subsequent phase, NWS broadened the scope of nuclear deterrence to encompass other weapons of mass destruction, including chemical and biological weapons (CBW). France, for instance, adopted this policy in the 1980s. In the US, the relevance of deterring CBW became apparent following the entry into force of the Biological Weapons Convention (BWC) in 1975 and the Chemical Weapons Convention (CWC) in 1997.

The current phase represents the third expansion of the scope. This evolution looks different for each NWS, as evidenced by their respective strategic documents. The US was the first to explicitly deter emerging technologies with nuclear weapons. The Trump administration’s 2018 Nuclear Posture Review referred to emerging technologies as a potential threat that might trigger a nuclear response, for the first time. The Trump administration argued that emerging technologies contribute to an “unprecedented range and mix of threats, including major conventional, chemical, biological, nuclear, space and cyber threats”. The Biden Nuclear Posture Review of 2022 reiterated this position.

In the 2021 Integrated Review, the UK explicitly refers to emerging technologies which could have an impact comparable to nuclear weapons as a threat to be deterred by nuclear weapons. However, London does not mention any specific threats. At the same time, French policymakers remain even more vague. The National Strategic Review 2022 emphasises that the purpose of French nuclear deterrence is to protect the country from “any State aggression against our vital interests, where it comes from and whatever form it takes”. Given this wide formulation, it can be assumed that it extends to threats beyond the traditional threats that the French nuclear force is meant to deter. It is possible that Paris considers nuclear deterrence to be an effective tool against cyberattacks, for example.

In contrast, Russia is very explicit in its articulation of the new technology threats that it would consider deterring with nuclear weapons. According to the Basic Principles of State Policy of the Russian Federation on Nuclear Deterrence of 2020, these include strike systems in outer space, non-nuclear high-precision and hypersonic weapons, unmanned aerial vehicles, and directed energy weapons. Notably, the document does not mention cyber-attacks.

Why is this shift problematic?

First, there is the substantial question of whether seeking to deter emerging technologies with nuclear weapons is an effective strategy. Although it is by no means clear what types of threats the UK or France, for example, seek to deter, one can assume that large-scale cyberattacks may be one of these threats. The US explicitly mentions cyber. The well-known pertinent attribution problem will, for the foreseeable time, hinder effective deterrence of cyberattacks. It is also possible for states to outsource malicious cyber activities to state-sponsored non-state actors who operate in a grey zone. The various state-sponsored hacker groups loosely affiliated with Russian state agencies provide evidence of this. Therefore, even if the attacker can be identified, in the case of non-state actors or state-sponsored groups, effective deterrence might not be possible (or not wanted as is the case for France).

Second, deterrence of non-nuclear strategic threats related to new technologies risks further blurring the lines between nuclear and non-nuclear strategic threats. It opens the door to new vulnerabilities and escalation risks. In an environment where there is already a lack of mutual understanding of each other’s doctrines, this development creates further confusion and uncertainty.

Third, such a policy contradicts the NWS’s pledge in the NPT context to reduce the salience of nuclear weapons. Although nuclear deterrence plays a significant role in the context of the war in Ukraine, the NWS have a special responsibility not to further broaden the role of deterrance to the extent that nuclear deterrence is perceived as a means of protecting states against any potential threat.

Fourth, this shift presents a risk that policymakers may be under the impression that any new technology-related threat can be dealt with by nuclear weapons. This not only leads to complacency by discouraging them from investigating alternative approaches to emerging threats, but it can also spur proliferation, as non-nuclear weapons possessors may consider nuclear weapons as a tool to protect themselves against any possible threats.

Recommendations

It would be desirable for the N5 to have a conversation, when the time is ripe, on their policies of deterring non-nuclear strategic threats, as part of their longstanding dialogue on nuclear doctrines. This would be compatible with National Security Advisor Jake Sullivan’s proposal to have a dialogue on the “guardrails for managing the interplay between non-nuclear strategic capabilities and nuclear deterrence”. Such a dialogue could address the question of which emerging capabilities states would consider deterring with nuclear weapons and the problems that arise when they do.

In the absence of any definition of a ‘strategic attack’, as emphasised in Pranay Vaddi’s June speech at the Arms Control Association, a public debate among experts and policymakers (at least in democratic states where such debate is feasible) is required to better understand the rationale behind deterring emerging technologies with nuclear weapons, and to explore potential alternative approaches. Furthermore, a debate is necessary to ascertain which of the potential threat scenarios could have strategic implications and whether alternative strategies, such as enhancing the resilience of critical infrastructure, might prove more effective. Crucially, there is also need for an N5 conversation on their doctrines, policies and understanding of strategic-level attack. In the NPT context this would provide an opportunity for non-nuclear weapon states (NNWS) to engage in a debate around these issues.

In terms of doctrines, the 2022 Nuclear Posture Review represents a shift towards a more conciliatory approach when compared to the 2018 review. For instance, the objective of reducing the salience of nuclear weapons was articulated as a goal in the 2022 review. The next US administration should at least continue to formulate the objective of reducing the role of nuclear weapons.

In conclusion, although this may currently not be feasible, it would be beneficial for the N3/N5 and, in general, the N9, to reach a consensus that the use of nuclear weapons to deter undefined new non-nuclear strategic threats could have destabilising effects and is therefore not a prudent approach. They should revert to the previously established policies that nuclear weapons, at most, deter the use of other weapons of mass destruction.

The European Leadership Network itself as an institution holds no formal policy positions. The opinions articulated above represent the views of the authors rather than the European Leadership Network or its members. The ELN aims to encourage debates that will help develop Europe’s capacity to address the pressing foreign, defence, and security policy challenges of our time, to further its charitable purposes.

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