Drawing on in-depth discussions at a series of workshops since February 2024, this report from the European Nuclear Study Group, of which Héloïse Fayet, research fellow at Ifri's Security Studies Center, is a member, evaluates five policy options discussed in European defense and security circles: 

• continued reliance on US extended nuclear deterrence (Option A)
• strengthening the role of British and French nuclear forces in European deterrence (Option B)
• developing a common European deterrent (Option C)
• pursuing new, independent national nuclear deterrents (Option D)
• investing in conventional deterrence without a nuclear component (Option E) 

Each option reflects a distinct way of distributing the costs and risks of nuclear deterrence between the United States, existing European nuclear powers, and nonnuclear European Allies, and each entails specific trade-offs between credibility, feasibility, legal aspects, and political risk.

None of these options is a good one: There is no deterrence ex machina, no low-cost or risk-free way out of Europe’s nuclear predicament. In the short term, continued reliance on US extended nuclear deterrence remains the most credible and feasible option available. It rests on unmatched military capabilities, deeply institutionalized cooperation within NATO, and decades of shared operational practice. Yet Europeans can no longer treat this option as a guaranteed baseline. Despite their efforts, Europeans may find themselves in a situation where the United States is no longer willing to provide nuclear deterrence. They must thus move beyond declaratory ambitions and engage seriously with the trade-offs, constraints, and risks of all options on the table.

Above all, Europeans can no longer outsource their thinking about nuclear deterrence to the United States. The era in which Europe could afford strategic complacency has ended. However uncomfortable the debate may be, the new security environment requires European policymakers to confront the role of nuclear weapons in the defense of the continent directly and without delay – and to invest the resources needed to do so competently. Thinking seriously about these questions today is the price of avoiding strategic failure tomorrow.

This report is available on the website of the Munich Security Conference.