Why would European countries need to develop a joint nuclear deterrence

by Francesco Nicoli

As long as Russia remains a hostile power on the European Union’s eastern border, the EU will depend on the security guarantee offered by the American nuclear umbrella. Should the United States withdraw this guarantee, the EU would be left without a nuclear deterrent against Russian aggression. In the short term, a commitment from France and the United Kingdom to buttress the American nuclear guarantees could fill the gap, but this is unlikely to be a stable long-term equilibrium. France and the UK lack sufficient capability to credibly shield Europe from Russia. Moreover, their commitment to Europe’s defence remains subject to domestic political cycles and national strategic considerations, and would therefore raise the same credibility issues as the current US guarantee.

In the long term therefore, if the US really does withdraw its nuclear umbrella from Europe, European countries faced with nuclear blackmail have little choice but to engage in either nuclear proliferation (everyone developing their own independent arsenals) or joint deterrence (a common nuclear deterrent). The former option poses obvious risks and might be too costly for some of the most-exposed countries. The latter option would require a substantial step forward in political integration, such as the establishment of a common political and military authority with power to make decisions over nuclear deployment, since credible nuclear deterrence cannot be subject to national vetoes. Without the US, European countries will eventually have to decide how they want to solve Europe’s nuclear trilemma.