U.S. President Donald Trump’s erratic policies and his disdain for NATO have weakened transatlantic security bonds and eroded trust in the credibility of the U.S. nuclear umbrella over Europe.
That is why the German government, and particularly the newly created National Security Council, started early in assessing options for a credible European nuclear deterrence mechanism in addition to the U.S. nuclear umbrella, as long as it holds.
As Berlin weighs next steps, here is an overview of the various channels through which the conversation about nuclear weapons — namely those of France and the United Kingdom — is progressing.
Firstly, the U.K.-France nuclear talks, which have been ongoing since 2010, were taken to a new level with the “Northwood Declaration” of July 2025. The communiqué put a “coordination” of both nations’ nuclear forces on the table for the first time.
Secondly, in October 2024, the defense ministers of Germany and the U.K. agreed on a German-British defense cooperation framework, the “Trinity House Agreement,” which was also intended to cover nuclear issues. However, this dialogue is still at a rudimentary stage.
Thirdly, Chancellor Merz and President Macron have agreed on a Franco-German nuclear dialogue. A high-level Steering Group is to conduct regular exchanges on all nuclear-related issues and develop opportunities for cooperation.
The fourth dialogue to start soon is based on the proposal of Friedrich Merz and Emmanuel Macron to extend the bilateral dialogue to other European NATO member states. Poland, Denmark, Sweden, the Netherlands, Belgium and Greece have already expressed interest. Should the U.K., Europe’s second nuclear power, join this initiative, it would result in an all-encompassing European nuclear dialogue modeled on the NATO Nuclear Planning Group.
These processes are only just beginning, and the initial focus is on developing a common understanding and formulating shared objectives within the various formats. In this regard, the British-French dialogue differs from the other formats because here two nuclear powers can discuss their respective nuclear doctrines on an equal footing, exchange nuclear-related data, or coordinate their operational principles and targeting.
The German-British, German-French and multinational dialogues, meanwhile, put their initial focus on the exchange of information and the building of trust between nuclear and non-nuclear states. Such trust is essential when it comes to matters such as the sharing of sensitive data or documents.
The conversations aren’t merely a dialogue for dialogue’s sake, but rather the development of a credible European deterrent based on the capabilities of France and the U.K. and – for as long as the U.S. so wishes – remaining linked to the American nuclear umbrella.
German considerations in that direction envision the following steps:
To begin with, the German-British and German-French dialogues can only be a starting point. Both formats must be expanded to include other European states as soon as possible. Only in this way can potential political reservations be overcome regarding the predominance of a Paris-London-Berlin connection as well as France’s history of a strictly national nuclear policy. Furthermore, representatives from the U.S. and Canada should always be invited to this expanded dialogue to underpin the transatlantic link.
Moreover, the dialogue should initially focus on political issues – such as the willingness of nuclear states to make a nuclear security pledge to their non-nuclear allies. The U.K. has already done so within the framework of NATO’s “extended deterrence,” while France has consistently opposed this concept and intended its nuclear weapons solely for the protection of its own territory.
Most recently, however, President Emmanuel Macron has proposed an idea of “advanced deterrence” (dissuasion avancée), thereby cautiously moving toward extended deterrence, albeit without explicitly saying so.
Furthermore, political guidelines could be drawn up for consultations between nuclear powers and their non-nuclear allies in the event of an imminent nuclear strike, as has been the case within NATO since 1962 — the so called “Athens Guidelines.” This does not restrict the nuclear states’ sole right to decide, but gives the allies the assurance that, in the event of a strike, they will at least be heard.
Non-nuclear states can provide various forms of compensation in return for the nuclear protection afforded to them. These could, for example, take the form of direct financial contributions. In the case of Germany, the Research Service of the German Parliament had already recognized in May 2017 that such nuclear co-financing is legally possible.
Nevertheless, a European nuclear deterrent, however it is structured, also requires adequate conventional defense. Here, Germany, as Europe’s largest economic power, bears a special responsibility. France and the U.K. are equally called upon, as a division of labor between the nuclear-armed states, which are left to focus on strategic forces while the other allies ensure sufficient conventional forces, is not realistic.
This will require painful steps in London and Paris to establish new financial priorities.
Karl-Heinz Kamp was a special advisor in the German Ministry of Defense and is an associate fellow at the German Council on Foreign Relations.
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