Can Europe do nuclear deterrence without America?

DONALD TRUMP’S pursuit of Greenland has revived an old argument: should more European powers seek nuclear weapons of their own? Consider Sweden. During the cold war the country secretly pursued nuclear weapons. In recent decades it has championed disarmament. But on January 10th Dagens Nyheter, one of Sweden’s largest newspapers, proposed a “joint Nordic” nuclear programme, perhaps alongside Germany. “What we see now may be the first signs of a political turnaround,” says Mats Knutson of SVT, Sweden’s public broadcaster.

Similar debates are flickering elsewhere. “In Germany there was a genuine nuclear taboo until last year,” says Alexander Bollfrass of the International Institute for Strategic Studies, a British think-tank. Now politicians are quietly discussing hedging against the withdrawal of America’s nuclear umbrella. Last year Donald Tusk, Poland’s prime minister, said his country might need nukes too.

For all this talk, the most important developments are taking place among the continent’s two existing nuclear powers. Britain has long committed its arsenal to NATO. France has not, but every French president since the 1970s has acknowledged a “European dimension” to the country’s vital interests. When President Emmanuel Macron offered to discuss the issue with European allies in 2020, he was largely ignored. At the time, trust in American extended deterrence—the promise to use its nuclear arsenal to defend allies—was solid. But last March, after Friedrich Merz, then chancellor-elect, expressed Germany’s interest, Mr Macron said he was opening “a strategic debate on using our deterrent to protect our allies on the European continent”. France formalised this intent in its national strategic review.

The closest France has come to making a binding commitment was the Northwood declaration with Britain in July 2025. The Chequers bilateral declaration of 1995 had stated that a threat to the “vital interests” of one country was a threat to those of the other, but last year’s undertaking went further. Britain and France agreed to “co-ordinate” use of their nuclear weapons, and stated that “there is no extreme threat to Europe that would not prompt a response by our two nations.”

The two countries set up a nuclear steering group, composed of top diplomatic and military officials, which met in December in Paris. There France for the first time invited Britain to observe its “Poker” simulation exercise, a quarterly demonstration of its airborne strategic nuclear force. A French defence official called it a mark of the “strong bilateral trust” established since Northwood.

Mr Macron is due soon to give another speech on France’s deterrent. He has ruled out any change to the country’s fully independent launch authority. This has not precluded detailed conversations with other European countries, notably Germany. “These things move very slowly,” says Bruno Tertrais, deputy director of the Foundation for Strategic Research (FRS), a think-tank in Paris. “But Germany at a very high level has shown itself willing to consider options that would have been unthinkable five years ago.”

European officials are coy about what those options are. On January 25th Ulf Kristersson, Sweden’s prime minister, said he had held preliminary discussions with France and Britain on nuclear-weapons co-operation, but that the talks were “not very precise yet”. One step might be for Mr Macron to more explicitly define the European dimension of French vital interests.

Another possibility would be joint nuclear-strike exercises with fellow European air forces (an Italian tanker aircraft took part in a French Poker exercise in 2022). That would create a stronger basis for wartime co-operation. Etienne Marcuz and Emmanuelle Maitre, also of the FRS, have argued that other countries could eventually provide naval support for nuclear submarines or strike support for France’s nuclear-armed aircraft, something that Swedish and Finnish warplanes have already begun doing for the current NATO nuclear-sharing mission, which involves American tactical nuclear weapons.

Going further, the French could deploy fighter jets from the nuclear-capable part of their fleet to Germany or other European countries, as they did (without their nuclear payloads) in Sweden and Poland last year. The most far-reaching option, mimicking the existing NATO scheme, would be to pre-position air-launched nuclear weapons in allied countries.

American officials sniff at the idea that the much smaller British or French arsenals could replace the American umbrella. Extended deterrence, they argue, requires a large and accurate arsenal capable of striking Russian missiles prior to launch, so that the damage to the country providing the guarantee could be limited. Only that would make it credible to use nuclear weapons to defend foreign soil.

French thinkers, leaning on the country’s doctrine of “strict sufficiency” in terms of nuclear warheads, retort that this is cold-war dogma. Many in Germany “buy the French argument…that the French offer is heavier on credibility”, because of its proximity, suggests Mr Bollfrass, “even if it’s lower on capability”. The unspoken problem is that credibility can change. France’s most popular party today is the populist-right National Rally. “If there’s a new French president soon,” he says, “that person might have a very different view of French national interests.” ■