US President Donald Trump’s stance on the war in Ukraine, his calls to annex Canada and Greenland, and loud complaints about insufficient contributions from NATO allies have raised doubts about the credibility of American commitments to the European security partnership. These concerns over the reliability of extended deterrence have sparked conversations about establishing an independent nuclear deterrent force in European capitals.
European anxiety over the viability of the transatlantic alliance and the nuclear guarantee is by no means a novel conundrum. The shift in US foreign policy priorities toward the Indo-Pacific has been a trend in the making since the Obama years. While the Biden administration has demonstrated a clear sense of urgency in addressing the China threat, it has also emphasized alliance cooperation and invested significant resources in the European theatre following Russia’s invasion of Ukraine. Under Trump, however, the shaping of agenda by a combination of Indo-Pacific prioritisation and “Fortress America” isolationism translates into the abdication of the US’ role as a primary security provider in the region. Despite Trump’s protestations and Vice President J D Vance’s heckling of allies in Munich, there has been no formal removal of the US nuclear umbrella from Europe. Nevertheless, the damage to American credibility is real.
Against this shifting backdrop, the role of nuclear weapons as the ultimate tool of deterrence against a revanchist Russia comes to the forefront in the European security calculus. Current concerns over the credibility of extended deterrence and the possibility of a Eurodeterrent force echo the dynamics of the Cold War-era transatlantic alliance. Despite the recognisable value of an independent nuclear deterrent, any such plan faces roadblocks and trade-offs, including the proliferation challenge. Consequently, European policymakers will have to confront competing policy considerations in responding to a deteriorating strategic environment.
Precedents from the Past
Since 1949, the US has formally extended its nuclear arsenals in service of the security needs of European allies. The extended deterrence guarantee has bolstered national security interests of transatlantic partners and has aided international stability by contributing to the nuclear non-proliferation regime. In Europe, except for Russia, the United Kingdom and France have developed nuclear capabilities of their own. The UK’s nuclear arsenal still relies substantively on US support but is operationally independent.
Europe’s fitful attempts to gain an independent nuclear deterrent date back to the 1957 formation of Euratom organisation, through which France, Italy, and Germany—under the guise of peaceful use of atomic energy—struck a deal to develop nuclear weapons. The plan was short-lived as France went on to pursue its own nuclear weapons program. Despite being part of the NATO alliance, France has consistently taken an independent stance on security issues under the banner of strategic autonomy. During the presidency of Charles de Gaulle, concerns over the US’ inability to trade New York for Paris led to the French withdrawal from NATO’s command structure in 1966. However, French collaboration with the US and other alliance partners continued.
More recently, French president Nicolas Sarkozy offered a nuclear sharing option to Germany, which Angela Merkel declined. Later, in 2020, President Macron again raised the possibility of a Europeanised French nuclear deterrent.
Potential Contingencies
The current debate on European nuclear deterrence beyond the extended US guarantee involves three different proposals. In line with a long tradition of strategic autonomy, President Macron has voiced considerations for putting the French nuclear arsenal in service of European allies’ security. The other option involves a joint Anglo-French Eurodeterrent force to secure allies and partners against Russia. Finally, Polish Prime Minister Donald Tusk has hinted towards the potential pursuit of nuclear option in addition to conventional military build-up.
The details of the French plan remain far from clear but Macron’s willingness to take up the mantle for continental security should be seen as a reassuring move. Both Poland and Denmark have already shown receptiveness to a French nuclear umbrella, even if only in an everything-on-the-table manner. On the French side, tensions between national prerogatives and alliance commitments regarding weapons sharing and command and control would need to be resolved in both the domestic political and diplomatic arenas.
In a sign of changing times, the joint Anglo-French extended deterrence initiative has a surprising backer in the next German chancellor Friedrich Merz. The shifting priorities are stark, given that Germany has traditionally been reluctant to respond to French calls for closer European military cooperation. The Labour Member of Parliament and the Chair of the United Kingdom Parliament’s Defence Committee also backed a greater role for the UK in European security affairs.
A potential Anglo-French deterrent plan envisages a combined nuclear force of around 515 warheads to tackle Russian threats. Narrowed in its focus on the European theatre, the plan is predicated on leveraging French submarine-launched ballistic missile and air-launched cruise missile capabilities as well as Britain’s operationally independent Trident II missiles. A viable joint deterrent plan would further require investment in conventional military upgradation along the Russian border, joint contingency plans, a European equivalent of the current NATO Nuclear Planning Group, and agreements over calibrated diplomatic signalling in crises situations.
The Polish interest in nuclear weapons might not amount to a concrete plan at this stage. But Tusk is openly echoing the option of nuclear proliferation—an option that other Eastern European strategists may also be considering. A heightened sense of threat perception, in the backdrop of waning American credibility, is only likely to lead to similar calls for nuclear proliferation in the Indo-Pacific theatre as well.
Teething Troubles
European states face technological, military and legal obstacles in the pursuit of nuclear weapons. The development of miniaturised bombs suitable for delivery is a highly complex technical process. Ensuring credible deterrence would involve substantive investment in a triad of delivery vehicles capable of surviving a first strike by the enemy. Finally, European proliferation would pose a challenge to the painstakingly built international nuclear non-proliferation regime. Nuclear proliferation can also increase the risk of inadvertent escalation among neighbouring European states as well as with Russia.
The limited stockpile of the British and French nuclear weapons pose a challenge to the credibility of the deterrent guarantee. The deterrent effects of a small stockpile would only be viable for a limited range of scenarios and will have to be complemented with conventional military build-up along Russian borders. Both France and the UK’s submarine-based deterrent options are not suitable for limited war contexts. Additionally, France would require more warheads, missiles, and Rafale aircraft in order to effectively utilize its air leg of deterrence capability. Another issue of concern would be the efficacy of joint command and control mechanisms in order to send credible signals, particularly considering the traditional French reluctance over any shared decision-making role for its arsenal. One may also expect pushback from domestic factional activists over the issue of stationing nuclear arsenals in other host countries.
Conclusion
Without a continued US nuclear backstop, an independent European deterrent force would face teething troubles. The lack of details about actual policy proposals from European states also means the debate remains limited to the level of strategic experts. Nevertheless, it has become an issue that is likely to gain resonance in the near future.
