The security rhetoric from the US has led European leaders to begin to doubt whether the US nuclear umbrella still covers Europe, which has created a debate about how Europe should relate to the new security order. Can Europe trust the US and the new Trump administration (Sorg, 2025)?
Since the Cold War, the US's extended nuclear deterrence has been a cornerstone of NATO's deterrence, especially since it is ultimately national nuclear weapons that constitute the alliance's nuclear deterrence (Aronsson, 2023). Nuclear deterrence is based on strategic and sub-strategic, forward-deployed nuclear weapons from the US, but is supplemented by the nuclear arsenals of the UK and France (NATO, 2022). A component at least as important as the nuclear warheads themselves are the delivery systems, the military command structure (for example, the NATO Nuclear Planning Group, NPG) and the national nuclear doctrines. The psychological effect of deterrence is largely based on these systems being jointly practiced, technically functional and that the doctrines are perceived as credible (Aronsson, 2023).
However, US security policy has changed fundamentally. After Donald Trump returned to the White House, he has been clear that the US will have a protectionist stance and that it is high time for Europe to pay for its own security (Erlanger, 2025). The risk that Trump would take the US out of NATO has been downplayed, but as commander in chief he has the mandate to decide where US troops should be stationed (The Constitution Annotated, nd). In addition, the president has control over the nuclear arsenal without the intervention of Congress or the Supreme Court, which has a direct impact on NATO and Europe (Ibid). NATO remains, but if deterrence is to be maintained, Europe needs to adapt to the new relationship with the US.
Therefore, I have identified three potential paths forward for Europe. The analysis assumes that the United States will remain part of NATO.
- That Europe continues to rely on American nuclear deterrence.
- Allow more countries in Europe to acquire nuclear weapons, beyond Britain and France.
- Expand France's nuclear arsenal to encompass all of Europe.
This analysis will mainly focus on the conditions for alternative 3.
Can Europe provide its own nuclear deterrent?
The United States has three different delivery systems for nuclear weapons (triad). Land-based intercontinental ballistic missiles with a range of up to 1,300 miles, Trident II D5 missiles with a range of about 736 miles aboard Ohio-class submarines, and strategic bombers such as the B-52 and B-2A Spirit. In total, the United States has about 1,770 strategic and substrategic nuclear warheads (Department of Defense, nd). The United States also has substrategic, airborne nuclear weapons forward-deployed at bases in Belgium, the Netherlands, Germany, Italy and Turkey (although under American control) (Masters & Merrow, 2023).
France has about 290 nuclear warheads. Unlike the United States, France has two delivery systems. Submarine-based ballistic missiles M51 with a range of about 1000 miles, on board four French Le Triomphant-class submarines. In addition, they have airborne cruise missiles on the French Rafale fighter jet, with a range of about 50 miles (Cameron, 2025). With two different delivery systems for both strategic and substrategic nuclear weapons, France has a diversification that increases freedom of action in both deterrence and second-order situations.
The UK has only submarines as a delivery system, with around 225 nuclear warheads (Messmer & O'Sullivan, 2025). The UK's Trident II D5 submarine-based ballistic missiles are carried on board four Vanguard-class submarines, which have a range of up to around 736 km. However, the UK only has one of its four submarines on patrol at a time. This creates a significant vulnerability after firing for the second-strike capability, as the submarine reveals its position after firing, giving the adversary a chance to knock out the submarine (Sorg, 2025).
The biggest argument for having nuclear weapons on submarines is the “second strike capability”, that is, the ability to destroy the opponent’s territory if they fire their nuclear weapons. The submarines constantly patrol the world’s oceans to prevent the opponent from being able to strike them, which allows for a nuclear response against the opponent’s territory.
Analysis
In light of the changing security policy tone from Washington, the European part of NATO needs to strengthen its freedom of action. In a situation characterized by increased uncertainty, future choices should be characterized by efficiency. Since the technical expertise and industrial capacity exist within Europe, further development of the nuclear doctrines of France and the United Kingdom appears to be the most realistic and effective alternative. Moreover, such an approach would not be in conflict with the Non-Proliferation Treaty (NPT) of 1968, which helps to avoid a nuclear arms race (IAEA, nd). However, it should be emphasized that there are significant challenges for both France and the United Kingdom.
France is outside NATO's NPG, which in practice means that they do not place their nuclear weapons at NATO's disposal, unlike the US and the UK. However, it is important to underline that decisions on the use of nuclear weapons within the framework of NATO's Article 5 are national decisions, which means that both the US President and the UK Prime Minister retain complete control over their respective countries' nuclear arsenals. France's nuclear doctrine is based on a strict national deterrence strategy, but French representatives have also emphasised that this capability indirectly strengthens the security of Europe as a whole (Maître, 2025).
The reader has noted that the UK's Trident missiles are the same as those used by the US. The missiles are produced in the US, while the nuclear warheads are produced and designed by the UK to meet the country's operational requirements (Tanneau, 2025). Every five years, the missiles are dependent on a “recertification”, software updates and technical maintenance, which can only be carried out by the US and Lockheed Martin (Messmer & O'Sullivan, 2025). The UK is therefore unable to operate the system independently of the US, which entails a significant dependence on American will.
France, unlike the UK, is completely autonomous. France has long been a strong advocate of autonomy from NATO and the US (Maitre, 2025). In 1966, France left the NATO command structure after conflicts over its incomplete control over its nuclear weapons program, but France rejoined in 2009, after several decades of independent defense planning.
President Macron has opened a dialogue on whether European countries could have a role in France's nuclear umbrella, indicating that France is potentially willing to take on the leadership role in European nuclear deterrence. However, France safeguards the independence in planning and implementing targeting and patrolling in its nuclear doctrine (Ibid).
The conditions for a European nuclear deterrent exist, but it would be a misjudgment to assume that the arsenals of Great Britain and France can fully compensate for a possible lack of American nuclear proliferation. In this case, it is positive that France's nuclear weapons program is autonomous from the United States, which creates freedom of action. However, limitations such as France's being outside NATO's NPG and Great Britain's structural dependence on the United States are two central components. In addition, the relative sizes of the French and Great Britain's arsenals, totaling approximately 515 nuclear warheads, constitute a strategic vulnerability. Furthermore, operational endurance is limited, as the two countries only have eight strategic submarines that can patrol with nuclear weapons, normally only two of these at a time.
Conclusion
One of the most effective and reasonable approaches to strengthening Europe's nuclear deterrent would be for France to join the NPG. This would increase deterrence by enabling the planning and training of France's nuclear forces within the framework of NATO's command structure, which is at least as crucial as the nuclear weapons themselves. The so-called "escalation ladder", consisting of a robust conventional capability combined with sub-strategic and strategic nuclear weapons with different delivery systems, helps to strengthen the threshold against aggression, thereby increasing deterrence.
There are many question marks, however. The analysis has not taken French domestic politics into account. In the event of an upgrade of France's nuclear arsenal, the French national debt is also a major issue – which, however, could have changed the analysis. French domestic politics is relatively shaky, with President Macron having two years left in his term of office, and what might happen in terms of security policy in the event of a change of power is also a question beyond this analysis. The French national debt is close to 115% of GDP, which can be compared with Sweden's approximately 32% of GDP (European Commission, 2024; European Commission, 2024). It should also be mentioned that joint European financing for procurement is possible. This would signal a show of strength from Europe in relation to both the USA and Russia.
The way forward, independent of the US
In order to enable a European nuclear deterrent independent of the US, France's reluctance to participate in the NPG constitutes a strategic constraint. France should consider joining the NPG to coordinate its nuclear capabilities within the NATO command structure and complement the UK's contribution to the alliance. Achieving a sustainable capability also requires an increase in the number of nuclear warheads, as well as the development of new delivery systems – in particular with a view to partially compensating for the possible absence of the US. Europe must also strengthen its conventional military capabilities. As part of increasing independence, consideration could also be given to reducing dependence on US weapons systems in future procurement, without completely ceasing defence cooperation.