Europe's Nuclear Shortcut Would Be a Strategic Mistake

The Trump administration’s release of the 2026 National Defense Strategy clarifies what European leaders have long suspected but perhaps preferred to ignore: Washington’s military commitment to the continent is no longer guaranteed. A reduction in American troop numbers across Europe is more likely than at any point in recent decades. Europe will now need to more seriously consider the necessary steps to provide for its defense in the absence of a large U.S. military presence. 

Some, including Mark Bell, Fabian Hoffman, and Lawrence Freedman, agree that Britain and France should extend their nuclear umbrellas to other European countries. They view a credible conventional European deterrent as unattainable, and nuclear proliferation across the continent as unacceptable. In theory, extending these nuclear umbrellas seems like a win-win solution for both proponents of nuclear nonproliferation and the withdrawal of American forces from the continent.  

In reality, this is a lose-lose situation. It would risk weakening Europe’s ability to deter Russia and further destabilize the environment between the two. Both Washington and European capitals should discourage such a policy. 

The central problem with extending the French and British nuclear umbrellas is its lack of credibility. It is questionable as to whether France and the United Kingdom would use atomic weapons to protect Eastern Europe. Threatening to use nuclear weapons to protect others is inherently less convincing than threatening to use them to defend one’s own country. Credibility is the name of the game with nuclear deterrence, especially deterrence that is extended to allies. Should Russia question this credibility, it would risk the breakdown Europe’s deterrent. 

This credibility problem does not end with potential adversaries. The credibility of military and nuclear threats also matter to allies. They fear abandonment from their security guarantors and frequently question whether their protector will risk its hide for their sake. To reassure allies, nuclear countries often adopt offensive strategies to signal to their allies that they are serious about using these destructive weapons. By striking first, a security guarantor attempts to limit damage to itself and protect its allies. France and Great Britain would be no exception. Extending their nuclear umbrellas would therefore require them to be willing to use nuclear weapons first in a crisis with Russia—a deeply destabilizing posture. 

The risks of that strategy are compounded by the imbalance between British and French nuclear forces and those of Russia. France has 370 nuclear warheads and the United Kingdom has 225, far below Russia’s 4,380 warheads. Non-nuclear European countries would be uneasy with this nuclear imbalance. While these arsenals may suffice for national self-defense, they are far less convincing when extended to protect the entire European continent. Moreover, other European countries would rightly question whether Paris or London are willing to protect them at the risk of near-certain devastation.  

European nations in NATO are more than capable of building a conventional deterrent. These nations possess comparable troop numbers and military equipment quantities to Russia. Moreover, Europe’s collective GDP eclipses Russia’s, permitting them to spend more on their militaries. By focusing on bolstering their conventional military capabilities, allied nations of Europe can deter Russian aggression, avoid nuclear proliferation, and lessen the chances of either side using nuclear weapons.  

Europe therefore faces a critical decision. It must choose between building up its conventional military capabilities and forces or permitting nuclear proliferation across the continent. While strengthening conventional military capabilities is more expensive and politically difficult, it offers a more stable and credible means of deterring Russia. Still, both alternatives—building up Europe’s conventional forces and nuclear proliferation— are immensely preferable to a strategy that increases the risk of nuclear war by placing Europe’s security on an unstable nuclear foundation.  

Preventing nuclear war should be the business of every nation. Opposing a British and French extension of their nuclear umbrellas helps achieve this shared mission. 

Benjamin Giltner is a policy analyst for defense and foreign policy at the Cato Institute.