The US nuclear umbrella over Europe was a myth

Is it possible to imagine that one state would risk its own destruction in defence of another state?

US President Donald Trump has always disliked military alliances, and NATO is no exception. Therefore, we must expect some form of American withdrawal from Europe. In Trumps view, Europeans can rearm and make American forces redundant. If not, they’ll have to face the consequences. In any case, the US will come out as a winner.

What was the American nuclear umbrella about?

This has sparked renewed interest in a European nuclear umbrella to replace the American one. Germany’s new Chancellor, Friedrich Merz, says he wants to speak with France and the UK about this, and Polish leaders are expressing similar views. In Norway, the idea of a Nordic nuclear force has been floated.

The first question to be answered is what exactly should be replaced. What does the American nuclear umbrella mean? This has been a sensitive issue ever since the Soviet Union developed a second-strike capability in the early 1960s. The US responded with a doctrine of “flexible response” and deployed tactical nuclear weapons in Europe, for massive retaliation against the Soviet Union was no longer a credible response to a Soviet attack.

During the Cold War, American nuclear weapons could be used against Eastern Europe and Soviet forces there, but not against the Soviet Union itself, as that would have been tantamount to suicide. This was no comfort to Western Europeans, however, because in a war between NATO and Warsaw Pact countries, the Russians could use their weapons against Western Europe. The arsenals became so vast — 7,000 weapons in Western Europe alone — that everything that should be defended would be destroyed.

The Europeans wanted a protective nuclear umbrella over Europe. Just like an umbrella protects against rain, a nuclear war should take place outside the umbrella. The Americans, however, had different ideas. They wanted to limit such a war to Europe - in other words, conduct the war within the umbrella to avoid that their own territory would be directly affected. The Russians had an equally obvious interest in the same. In 1979, as a new round of rearmament and intense Cold War tension was looming, former US Secretary of State Henry Kissinger reminded Europeans not to ask for guarantees “that we cannot possibly honour.”

This remained the situation until the Cold War ended, and the European political map was redrawn.

Shifting from nuclear to conventional deterrence

Today, nearly all of Eastern Europe has become part of NATO, so bombing NATO and EU partners with nuclear weapons to thwart a Russian attack would be deeply problematic - especially for Europeans, but also for the US. The fact that five European countries host American nuclear weapons for joint use — US weapons on European aircraft – is often claimed to be the glue that holds the alliance together. However, for the credibility of the US nuclear guarantee it makes no difference. It is a leap of logic elevated to a higher form of wisdom.

Belarus remains allied with Russia. In some NATO exercises involving nuclear weapons it has therefore been the simulated target, in keeping with Cold War thinking. In today’s Europe, however, it makes little sense. In other exercises, conventional weapons have been used instead, and that’s where the thrust of future planning should be. Accurate hypersonic missiles travelling between 5 and 30 times the speed of sound are already being phased in.

The Russians were first, but the US and Europe are following suit. These missiles are weapons that can destroy aircraft before take-off, missiles before launch, and submarines while still in port. They can replace nuclear weapons in these roles.

This doesn’t mean that nuclear weapons are being phased out. Many Russian missiles are dual capable, and the US is developing a new nuclear missile for its B-52 and B-1 bombers. Both sides are planning for nuclear warfare using low-yield weapons. For example, the nuclear bombs for the F-35 fighter jets have adjustable yields as low as 0.3 and 1.5 kilotons (the Hiroshima and Nagasaki bombs were between 10 and 20 kilotons). But the emphasis is shifting from nuclear to conventional weapons, based on a growing realization that resort to nuclear weapons would be a rod for one’s own back. Conventional deterrence is more credible.

France won’t sacrifice Paris for Oslo

Sometimes, it is noted that a war between nuclear powers could spiral out of control, leading the US to use nuclear weapons against Russia in defence of Europe. As long as the chance of this happening is a figure above zero, there is a deterrent effect. But it is foolhardy to base one’s own strategy on something going wrong. This is no less true for the Europeans than for others. With this thin qualification, the American nuclear umbrella over Europe was therefore a myth. For the future, European countries should stake their defences on conventional weapons, eschewing the risk of catastrophic nuclear warfare.

This is where the French and British nuclear arsenals enter the picture. The French built their weapons independently, without relying on others. The British did not: they have four nuclear submarines armed with American missiles and warheads based on American designs, which limit their freedom of action.

Could a European nuclear force be developed based on these arsenals? Some leaders and commentators profess to believe so. But the same logic applies to French, British and US thinking: is it at all conceivable that a state would risk its own total destruction to defend another state?

The French said “no”. President Charles de Gaulle famously stated that the US would not sacrifice Chicago for Paris — and that only a national finger on the nuclear trigger would do. France won’t sacrifice Paris for Oslo or Lyon for Helsinki.

No good answer exists

For France to run such a risk, it would have to be because another state's territory is judged to be inseparably linked to French security. Would Germany qualify? The French say they are open to discussing a broader European role for their nuclear weapons, but so far no one has explained what that would mean.

Probably because there is no good answer. The same applies to the British. They say their nuclear force is dedicated to NATO’s defence - but meaningful elaboration is missing.

The solution is not to mimic the Americans by spreading French and British nuclear weapons across the continent. Nor is it to expand and modernize those arsenals. That won’t solve the credibility problem. In the end, the same limitation applies to the French and British as to the Americans. They are not suicidal.

A sad derailment of the debate

What about a European nuclear force - or a Nordic one? The insurmountable obstacle lies in the decision-making structure. Control over nuclear weapons lies at the very heart of national authority. Decisions are for the innermost chambers of government to make. Only heads of government have the power to press the button and decide over life and death. The idea that European integration will go so far as to create a shared nuclear command is beyond belief. The idea that the five non-nuclear Nordic countries could build their own nuclear arsenal and become a single nuclear power is pure fantasy.

Poorly conceived ideas about nuclear deterrence are therefore a sad derailment of the current debate on European security. Rather than addressing the serious challenges that have emerged, they risk making an already dangerous situation even worse. Efforts should instead be focused on how to build credible conventional deterrents and on arms control measures to stabilize such postures.

• Sverre Lodgaard is a Senior Research Fellow Emeritus at the Norwegian Institute of International Affairs. He is a former Director at PRIO.
• This text was first published in Norwegian in Aftenposten 28 May 2025.