Strengthening nuclear deterrence
Updated: 5 days ago
By Peter Watkins
Context
This debate takes place against the backdrop of mounting concerns about potential Russian aggression against Europe. Within the EU, the commissioners from the Baltic States, Poland and Finland wrote to Commission President Ursula von der Leyen on 30th July warning of a "deteriorating security environment" amid an "increased frequency of airspace violations and drone incursions." Another portent was CIA Director John Ratcliffe’s surprise visit to Moscow on 25th August, reportedly to warn the Kremlin against attacking US allies.
So far, Russia’s threats against Ukraine’s European partners have been at the ends of the spectrum of conflict. Threats of nuclear use were made by Putin himself on 24th February 2022 – and have been repeated by senior figures and media pundits with links to the Kremlin. In parallel, the last four years have seen an upsurge in so-called hybrid attacks, including a growing number of physical attacks on industrial facilities as well as drone incursions. Thus far, Russia has not threatened a NATO country with conventional military attack – although fears of a limited incursion remain.
All this is occurring as the US reduces its commitment to European security, partly by accident – the war on Iran which has exposed the limits of US power – and partly by design – the reordering of strategic priorities in the National Security Strategy and the conventional force reductions reportedly briefed to NATO in June. US officials have so far given no indication of a weakening of the Administration’s commitment to extended nuclear deterrence.
Challenges
The (growing) risk for European allies is that an (increasingly desperate) Kremlin starts to believe that a combination of nuclear threats and mounting hybrid attacks will induce creeping paralysis across the Alliance, enabling it to prevail in Ukraine (as Western support ebbs away) and then to neutralise individual NATO/EU states by one means or another. While Allies’ priority should be enhancing resilience against hybrid attacks, this should be accompanied by measures to deter any Russian efforts at nuclear blackmail encouraged by a (hopefully false) perception that Washington DC will not be engaged.
For much of the past 15 years or so, NATO has not been unduly alarmed by Russia’s extensive sub-strategic nuclear arsenal and intermediate range dual-use delivery systems. While these vastly outnumber NATO’s in-place nuclear forces – the Dual Capable Aircraft (DCA) equipped with the US-provided B61-12 bomb – the presumption has been that sub-strategic use would be deterred by NATO’s overall mix of nuclear forces, including the strategic forces of the US (the nuclear “Triad” and AGM-86 cruise missiles carried by US strategic bombers) and the independent nuclear forces of the UK and France. NATO’s published nuclear policy has changed little over that period. The restatement in the 2016 Warsaw Summit declaration – including the first explicit endorsement of certain key aspects of British and French nuclear doctrine (such as the “separate centres of decision-making”) – was incorporated almost verbatim into the 2022 Strategic Concept.[1]
In parallel, however, Russia’s published nuclear doctrine has been evolving. The November 2024 update both broadened the range of scenarios in which the Kremlin might employ nuclear weapons and lowered the threshold for doing so.[2] It is conceivable that the Kremlin would consider using its sub-strategic weapons to destroy NATO conventional forces which were about to expel Russian forces occupying the territory of an Ally – believing that NATO’s nuclear powers would not respond to such limited nuclear use with strategic weapons. To forestall such thinking, NATO needs credible sub-strategic options. During the Cold War, European Allies feared that the Kremlin might have a “misconception” that “at some critical point as a conflict developed the US would hold back”.[3] Given the behaviour of the current US Administration, the risk of such a misperception must now be considerably higher.
Options
The logical response to such concerns would – as with the UK’s and France’s decisions to build independent nuclear deterrents – be for European Allies to invest in nuclear systems that were not dependant on US decision-making in a crisis. Analogous efforts in the late 1950s and 1960s such as the Multilateral Force (MLF) and the UK proposal for an Atlantic Nuclear Force (ANF) came to nought – they were cumbersome and did not resolve the basic problem of control. So European Allies had to live with the strategic ambiguity.
The idea of a multilateral European Nuclear Force re-emerged in late 2018 and again in 2024 – and has been the subject of some analysis by commentators. Such a force could plausibly comprise a jointly owned fleet of nuclear-armed submarines and/or a fleet of dual capable aircraft armed with cruise missiles or gravity bombs. There would also be a multilateral military command centre reporting to a political decision-making entity – most likely a collective body, perhaps the European Council augmented by non-EU participants.
There are a number of practical challenges, as the commentators have noted. First, setting up the European force would take considerable time in an already deteriorating geopolitical environment. Secondly, the ownership of nuclear weapons by a new entity representing over two-dozen currently non-nuclear weapons states would be contrary to the provisions of the Non-Proliferation Treaty (NPT). Thirdly, any collective decision-making body would be sub-optimal operationally – it could be paralysed by absences or obstruction. The Kremlin would be aware of that possibility, weakening the deterrent value of the force.
The changing role of the UK and France
The UK and France’s respective nuclear policies, postures and capabilities have changed little over decades. The UK has an “independent, minimum, credible nuclear deterrent” – assigned to NATO. Since the late 1990s, the UK nuclear deterrent has had only one delivery system – four nuclear-armed submarines carrying US-sourced Trident ballistic missiles with UK-manufactured warheads. France also has an “independent” deterrent to deter threats to its “vital interests” – but not assigned to NATO. It has retained both a sea-launched and an air-launched leg, the latter comprising Rafale aircraft with stand-off missiles.
This largely constant picture has changed over the 14 months with three major decisions. First, the UK Government announced at the NATO Summit in June 2025 that it would join NATO’s DCA mission, pledging to procure twelve F-35A aircraft able to carry US B-61 nuclear bombs”.[4] Unstated was that these aircraft could carry a sovereign sub-strategic weapon were that to be developed in the future. Second, in July 2025, the Franco-British Northwood Declaration announced that the two governments had decided to “deepen their nuclear cooperation and coordination”.[5] Thirdly, in March 2026, President Macron announced the concept of “forward deterrence”, starting to put some substance to his previous somewhat Delphic suggestion that France’s vital interests have a “European dimension”.
While welcome, these steps do not match the extent to which the strategic environment is deteriorating. Additional steps should include:
On the assumption of continuing US engagement, further strengthening NATO’s DCA mission. Measures could include involving additional nations (such as Finland and Poland) and investing in a long-range stand-off weapon. The former needs to be assessed carefully to mitigate the risk of it being more provocation than deterrent: there are intermediate levels of involvement (e.g. access to existing weapon vaults rather than constructing new ones).
To reinforce the implicit message in the Northwood Declaration that, in any future crisis in which US intentions seemed uncertain, Moscow would need to take into account the combined destructive power of the UK and French nuclear forces, UK conventional forces could play a visible role supporting the French Air Force’s Pokernuclear exercises.
The UK-Germany Trinity House Agreement of October 2024 contained a provision to establish a “dedicated sub-group on nuclear issues”[6]. Without creating the deterrence-weakening impression that operational decision-making was being diluted, the UK government could more actively profile such bilateral dialogues to underline the UK’s contribution to extended deterrence (complementing the arrangements which France has been negotiating with a number of countries following President Macron’s speech).
The UK’s declaratory policy as currently stated in official documents and on the MOD website has changed little for years apart from becoming increasingly vague and bland. The UK Government needs to update – and sharpen the tone of – this material without diverging from the policy of being “deliberately ambiguous” about the exact modalities of nuclear use.
Looking forward, as a hedge against further strategic uncertainty including the potential emergence of a “two peer” challenge as Russian-Chinese ties deepen, the UK should actively explore the costs and industrial implications of (re)acquiring a sovereign nuclear sub-strategic capability.
Bio
Peter Watkins was the Director General responsible for international security policy in the UK Ministry of Defence 2014-2018. Among a number of academic and think-tank affiliations, he is now a Visiting Professor at King's College London and a Visiting Senior Fellow with the London School of Economics.
[1] NATO, NATO 2022 Strategic Concept, 29 June 2022, page 8.
[2] Ministry of Foreign Affairs of the Russian Federation, Fundamentals of State Policy of the Russian Federation on Nuclear Deterrence, 3rd December 2024, https://www.mid.ru/
[3] UK Ministry of Defence, The Future United Kingdom Strategic Nuclear Deterrent Force, July 1980, pages 3 & 5
[4] No 10 Downing Street, Press Release, UK to purchase F-25As and join NATO nuclear mission as Government steps up national security and delivers defence dividend, 24th June 2025
[5] No 10 Downing Street, Press Release, Northwood Declaration, 10th July 2025
[6] Ministry of Defence, Policy Paper, Agreement on Defence cooperation between the Ministry of Defence of [the United Kingdom of] Great Britain and Northern Ireland and the Federal Ministry of Defence of the Federal Republic of Germany, 23rd October 2024.
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