Recently published Signal discussions in which senior Trump administration officials admit they “hate bailing out” America’s “pathetic” European allies have cast fresh doubt on the U.S. commitment to defending Europe. Even before these revelations, what Poland’s Prime Minister Donald Tusk described as “a profound change of [sic] American geopolitics” had already provoked reappraisals across Europe of the future of nuclear deterrence on the continent.
In this new reality, Washington’s European allies are faced with three options: continue to rely on what they consider a weakened security guarantee backed by U.S. extended nuclear deterrence; pursue further nuclear proliferation; or develop an independent deterrent comprising the nuclear forces of France and the United Kingdom.
Each of these options are less desirable than U.S. extended deterrence before Jan. 20, 2025. The question, however, is how the European NATO members can best react to safeguard their collective defense, given the feasible alternatives today. Under current conditions, the transition to an Anglo-French “Eurodeterrent” is the best option for Europe.
A Shaky U.S. Extended Deterrent
The fundamental nature of the crisis afflicting U.S. extended nuclear deterrence to NATO is one of credibility. The U.S. commitment rests on Article 5 of the 1949 North Atlantic Treaty, which requires each ally to respond to an armed attack against any one of them with “such action as it deems necessary, including the use of armed force.” The deterrent credibility of this commitment requires U.S. willingness to risk and ultimately wage nuclear war on behalf of allies located thousands of miles away.
Deterrence theorist Thomas C. Schelling recognized that the U.S. commitment to defend the “homeland” was “inherently credible,” but the pledge to defend “allies” at “great cost and risk, requires more than military capability. It requires projecting intentions.” In addition to forward-deployed forces, Schelling emphasized the importance of America’s “political” commitment of its “honor, obligation, and diplomatic reputation” to the defense of its allies in making extended deterrence credible.
Since Jan. 20, the U.S. government has undermined this political commitment. President Donald Trump has said that the United States would not defend NATO members that fail to meet unspecified spending targets. Several administration officials have also expressed territorial ambitions toward NATO members Canada and Denmark. The United States suspended military and intelligence assistance to Ukraine to pressure Kyiv to make concessions in peace negotiations while doing nothing to force Russia into any reciprocal moves. Ukraine is not a NATO member and the United States is not treaty-bound to defend it. Nonetheless, these developments have spurred NATO allies’ reconsideration of their reliance on U.S.-made weapons systems.
Trump’s admiration for Vladimir Putin, Vice President JD Vance and Elon Musk’s support for the far-right Alternative for Germany, and administration actions that have undermined the domestic rule of law have also challenged Europeans’ belief that the United States still shares basic values and norms with them.
None of these moves constitute a formal removal of the U.S. nuclear umbrella from European NATO territory. Collectively, however, they have significantly undermined NATO allies’ confidence that the United States is committed to their defense against external attack. Anxieties over U.S. nuclear credibility are manifest in French President Emmanuel Macron’s call for a debate on European deterrence, incoming German Chancellor Friedrich Merz’s suggestion that France and Britain could “share” nuclear weapons with Berlin, and Tusk’s discussion of Poland’s nuclear options.
The extent and heedlessness of this damage to the trans-Atlantic alliance constitutes a fundamental departure from past U.S. policy. Even if previous administrations doubted the solidity of extended deterrence, expressed frustration with their European allies in private, and publicly exhorted them to raise defense spending, U.S. officials never cast doubt on America’s will to defend its European allies in anything approaching the open manner of recent weeks.
Given the speed with which the Trump administration has moved in its first two months, Europe has no guarantee that Washington will not take even more significant steps over the next four years. This could include refusing to appoint a U.S. general officer as NATO’s Supreme Allied Commander Europe, or withdrawing or redeploying U.S. conventional or nuclear forces from European NATO territory. These steps could further damage the credibility of the U.S. nuclear umbrella. This prospect lends urgency to European consideration of alternatives now.
Two former Biden administration officials have recognized the challenge that this “crisis of confidence” represents. They propose that Europe requests the United States to reaffirm its commitment to the continent’s security by reiterating previously stated policy, “backstopped by the full capabilities the U.S. military could bring to bear in a conflict.” Others have suggested that the administration address European qualms over the strength of extended deterrence though changes to U.S. force posture, more coordination with allies, and consultative mechanisms.
However, any reiteration of previous declaratory policy would lack credibility: Trump and his lieutenants have already told Europe what they really think about America’s stake in its security, and they are likely to undermine any such recommitment through future statements or actions.
Nor are adjustments to the U.S. nuclear posture or consultative mechanisms likely to bridge the credibility gap. Forward-deployed nuclear forces, increasingly elaborate capabilities designed to limit damage to the United States and its allies in a nuclear war, and consultative mechanisms such as the NATO Nuclear Planning Group are the manifestation of the U.S. commitment to defend NATO territory with nuclear weapons, not a replacement for it. While the withdrawal of U.S. forces or abolition of nuclear consultation would spell the definitive end of the U.S. nuclear umbrella, modifications in these areas would do little to repair the credibility of U.S. extended deterrence if the publicly stated commitment is not solid.
Simply waiting Trump out in the hope that a more orthodox U.S. administration takes office in 2029 is not a viable strategy either. Even if such an administration assumes power, there is no guarantee that the United States would not swing back to a more confrontational posture in 2033. Europe needs to come to terms with a future in which the U.S. commitment to its security will, at best, fluctuate.
Europe should therefore consider other options to secure itself.
The choice Europe faces is not between U.S. extended deterrence as it existed before Jan. 20, 2025, and other arrangements. Instead, the choice is between today’s compromised U.S. commitment — which may deteriorate rapidly and oscillate unpredictably in the future — and the alternatives.
The Destabilizing Prospect of Nuclear Proliferation in Europe
At present, the debate in Europe has turned to whether more countries should develop nuclear weapons. Analysts across the continent have argued that their governments should consider doing so. Tusk has hinted that Warsaw should consider acquiring its own nuclear deterrent. In Norway, commentators have debated a nuclear force for the Nordic region, though the Norwegian government has rejected the idea.
Nuclear proliferation is a superficially appealing course, given the existential security guarantee that a fully developed nuclear arsenal can provide. Any nuclear program, however, would encounter significant technological, legal, and military challenges that could undermine the security of a nascent nuclear power.
For starters, developing a nuclear arsenal is technologically demanding. While building a crude nuclear weapon is within the capabilities of a modern industrial state willing to bear the cost, it would take significant time and resources. No non-nuclear weapon state in Europe can dash to a bomb and acquiring the necessary industrial infrastructure would be very difficult.
Militarily, a crude aircraft-delivered fission gravity bomb would not be a sufficiently credible deterrent to external attack. Minimum deterrence requires that a state can reliably inflict unacceptable damage on an adversary. Guaranteed retaliation with unacceptable damage requires nuclear forces that can survive or preempt any enemy strike and penetrate defenses to deliver the weapons to target. As such, no nuclear weapons state currently relies on gravity bombs delivered by aircraft. Instead, nuclear powers at a minimum have developed ballistic missiles to deliver miniaturized nuclear warheads. Even then, stationary missiles are vulnerable to attack. Unless a state is willing to fire its missiles at the mere warning of an incoming strike, it needs to ensure survivability for its nuclear forces through mobile ground launchers, sophisticated aircraft, or submarine-launched ballistic missiles.
Moreover, if a new European country were to acquire nuclear arms, or announce its intention to develop them, it would shatter the Treaty on the Non-Proliferation of Nuclear Weapons. All European countries are parties to the treaty and under its terms all non-nuclear states have agreed never to acquire nuclear weapons. In exchange, nuclear parties have agreed to share the peaceful benefits of nuclear technology and to pursue disarmament. The defection of a European country from the non-proliferation treaty would damage the nonproliferation norm and the effectiveness of the treaty. This, in turn, may increase the risk that countries such as Iran, South Korea, and Japan would acquire nuclear weapons. This would spell the end of the international nonproliferation regime.
The prospect of a new European nuclear power would likely provoke a significant reaction from any country that viewed it as a threat. This could include sanctions, but also military action to prevent the breakout state from acquiring nuclear weapons or destroying its emerging capability. As such, a new nuclear-weapons program would risk decreasing rather than increasing a European country’s security.
Any European country that obtained nuclear weapons would be incentivized to pursue a risky nuclear strategy. If the new nuclear state were small, with key cities near the Russian border, or had relatively weak conventional forces, then it would be highly motivated to launch a nuclear attack at the outset of a Russian invasion. Knowing that the country’s forces were on a hair trigger would incentivize Russia to launch a pre-emptive strike against that state, further increasing the pressure on the target state to pre-empt Russia by launching its nuclear weapons first. This escalatory spiral would dramatically raise the risk of nuclear war in Europe.
Despite these risks, if “front-line” European NATO allies conclude that they no longer have faith in U.S. extended deterrence, and absent any viable alternative, it is likely that some would seek their own nuclear arsenals.
A Third Way: An Anglo-French Eurodeterrent
Given the perceived damage that the Trump administration has done to the credibility of U.S. extended nuclear deterrence and the dangers associated with further European nuclear proliferation, it is important to consider the potential of a replacement: nuclear deterrence based on the combined strength of France and the United Kingdom.
As several analysts have pointed out, an Anglo-French Eurodeterrent would be less militarily capable than U.S. nuclear forces. The United Kingdom and France currently have a combined stockpile of approximately 515 nuclear warheads. France can deliver these warheads by submarine-launched ballistic missile as well as air-launched cruise missiles carried by ground- and carrier-based Rafale aircraft. Meanwhile, Britain relies solely on a submarine-launched ballistic missile force. While operationally independent, the British force uses the U.S.-supplied Trident II missile. These missiles are maintained in the United States, and the United Kingdom’s nuclear warhead and submarine programs are tightly integrated with America’s.
To be sure, an Anglo-French nuclear force could not replace the United States’ 3,700 deployed and operational reserve warheads in sheer numbers of weapons, or match Russia’s enormous 4,380-warhead operationally available stockpile. Nor could it replicate Washington’s potential ability to limit damage by pre-emptively striking Russia’s nuclear forces, or its range of options for sub-strategic nuclear use.
However, an Anglo-French force would not need to match U.S. capabilities. The size of Washington’s arsenal and the diversity of its weapons systems and nuclear options are products of its historical role as the provider of extended deterrence for a range of far-flung treaty allies in Europe and the Indo-Pacific. This force, as stated U.S. policy attests, is designed not only to deter nuclear weapons use and “emerging non-nuclear threats,” but also to ensure that the United States will not be deterred from intervening conventionally on behalf of its allies worldwide. France and the United Kingdom, on the other hand, could be able to focus their nuclear postures on deterring a narrower range of scenarios within Europe, where the two countries’ vital national security interests are manifest.
A European conventional military buildup of the type currently proposed would help narrow this range of scenarios significantly and alleviate the credibility problem that besets the U.S. deterrent. A large-scale forward-deployed European conventional force to defend NATO territory, including British and French units, would render any uncertainty regarding conventional intervention moot: The decision to fight at the conventional level would not rest solely with France or the United Kingdom in the same way it currently does with the United States. Yet French and British units would be involved at an early stage, thereby ensuring that Paris and London would be committed.
European forward-deployed conventional forces, for example in the Baltic states, Poland, and the Nordic region, capable of effective defense from the start of a Russian invasion, would mean that the United Kingdom and France would not have to credibly threaten nuclear first use in the same way as a bordering nuclear state would, or as today’s U.S.-reliant NATO might have to. The United Kingdom and France could instead focus on deterring Russian limited and large-scale nuclear attacks when Moscow was losing a conventional battle against a European coalition defending NATO territory. The development of such a European conventional force would not be easy or quick, but it would ease the credibility problem inherent in nuclear first use significantly.
With their ability to hold several key cities in European Russia at risk, including Moscow and St. Petersburg, even if Russia struck first, the submarine-launched missiles of the United Kingdom and France would provide a sufficiently credible force to deter large-scale Russian nuclear-weapons use against Europe. To maintain the long-term viability of this submarine force, the United Kingdom and France would have to develop joint contingency plans well beyond existing cooperation to cope with any cutoff of U.S. nuclear assistance to London.
Further development of an air-delivered missile capability would be necessary to provide a credible limited-use capability beyond the “final warning” of current French doctrine and the rumored low-yield submarine-launched ballistic missile warhead available to the United Kingdom. Such efforts would require an increase in warhead numbers, though not on par with U.S. or Russian stockpiles.
A new generation of conventional precision-strike systems should supplement the Anglo-French nuclear forces. Non-nuclear allies such as Germany, Poland, the Netherlands, and the Nordic states could provide such systems, possibly through joint production. This role would draw non-nuclear states deeper into conventional-nuclear operations through exercises and planning that go beyond non-nuclear NATO members’ current involvement in Conventional Support for Nuclear Operations. Coordination of these nuclear and non-nuclear efforts should be institutionalized in a European equivalent of the existing NATO Nuclear Planning Group, in which France does not currently participate.
A new Anglo-French deterrence policy would need clear articulation by London and Paris, either in a single document, or in separate but coordinated statements, similar to the U.S. Nuclear Posture Review. Neither country currently has such a detailed declaratory policy. Greater specificity would be necessary to bolster the credibility of an Anglo-French deterrent in the eyes of Moscow. Such a policy would also provide reassurance to non-nuclear European allies, who would need to be involved in its formulation in a similar way as with the U.S. Nuclear Posture Review.
The financial, military, diplomatic, and cultural challenges facing any Anglo-French deterrent would be formidable and require a “paradigm shift” in Europe’s approach to nuclear deterrence. However, the Trump administration’s public disregard for U.S. extended deterrence, the growing danger from Russia, and the rising risk of further nuclear proliferation, means that the settled paradigm of trans-Atlantic deterrence is already shifting in ways that will compel Europe to choose between these options. The development of an Anglo-French Eurodeterrent — ideally as part of a negotiated transfer of responsibility for European security from the United States to its NATO allies, could help Europe navigate a path from this old world to a more secure future.
James Cameron is associate professor of Modern North American History at the University of Oslo. He is the author of The Double Game: The Demise of America’s First Missile Defense System and the Rise of Strategic Arms Limitation (Oxford University Press, 2018). Follow him on BlueSky at @jjjcameron@bsky.social.
Photo: SAC Rob Bourne/MOD
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