Europe’s nuclear question: deterrence, dependency and the search for strategic sovereignty

The debate over a European nuclear deterrent — long confined to the margins of strategic discourse, treated as a taboo in Berlin, a doctrinal provocation in Paris, and a distraction in London — has entered the mainstream of European security policy with unprecedented urgency in 2025 and early 2026.

Three interlocking forces have driven this shift: the sustained signals from the Trump administration that the United States may no longer unconditionally guarantee European security under Article 5 of the North Atlantic Treaty; the expiration of the New START arms control treaty on February 5, 2026, eliminating the last major U.S.-Russia nuclear verification regime; and Russia’s demonstrated…

This analysis answers: How have Trump-administration signals over Article 5 guarantees reshaped the European nuclear-deterrent debate in Berlin, Paris and London? What are the strategic consequences of the New START treaty's expiration on 5 February 2026 for European security? How do dependency on the US umbrella and the search for strategic sovereignty interact in a possible European deterrent? What options and constraints face Europe if it pursues an autonomous nuclear-deterrent posture?