Nuclear deterrence: The question Europe's defense boom can't answer

BRUSSELS (CN) — Europe’s biggest joint defense project was supposed to prove that France and Germany could build the future together. This week, it fell apart.

The Future Combat Air System (FCAS) — a next-generation fighter paired with autonomous drones and a shared battlefield network — was launched in 2017 as a 100 billion-euro bet on European military independence. German Chancellor Friedrich Merz killed it this week in a sentence: France wants its next fighter to carry nuclear weapons and launch from aircraft carriers. “That’s not what we currently need in the German military,” he said.

Belgian defense minister Theo Francken was more direct: “FCAS is dead,” he posted on X.

On the surface, the program collapsed over an industrial turf war between France’s Dassault and Germany’s Airbus — years of disputes over workshare and technology ownership, never resolved, just deferred. But the deeper problem was simpler: France and Germany were never building the same plane. France came with nuclear weapons and aircraft carriers. Germany came with a NATO membership card and no nuclear mission.

The collapse comes as Europe is spending more on defense than at any point since the Cold War — and confronting, for the first time in decades, what happens if the U.S. nuclear umbrella goes away.

At Munich last week, Macron and Merz announced a “strategic dialogue” on extending France’s deterrent to European allies. Macron went further than any French president before him, floating the possibility of “command capacities at the European scale” — a significant departure from France’s long-standing position that its arsenal is a strictly sovereign tool.

He’s due to give a speech on French nuclear doctrine before the end of the month.

On Thursday, European Council President António Costa went further: France and the U.K. “are talking with other European countries in order to look at how they can offer a common nuclear deterrence to all the European countries.”

The fighter jet debacle shows how hard that will be.

“Words are cheap, even treaties are cheap,” says Francesco Nicoli, a researcher at the Brussels-based think tank Bruegel who co-wrote a paper on Europe’s nuclear options. “What matters is whether you really believe — and especially if your opponents really believe — that the country guaranteeing for you is willing to make the literal ultimate sacrifice to protect you.”

The stakes are most acute on NATO’s eastern edge, where Baltic states like Estonia sit within striking distance of Russian forces. The assumption running through this week’s debate is that a French guarantee is more credible than a U.S. one. Nicoli’s argument is that it isn’t — a French president facing a nuclear decision over Tallinn faces the same calculus as an American one.

The most immediate option is for France and the U.K. to extend their existing deterrents to cover the continent. But neither country is offering an umbrella in the U.S. sense.

As Emmanuelle Maitre of the Fondation pour la recherche stratégique points out, France’s position is narrower: Paris would respond to an attack on Europe only if it judged its own core interests to be at stake. “The key concept regarding France is that the French vital interests … may have a European dimension,” she told Courthouse News.

Washington’s guarantee to defend Tallinn carries no such condition.

The arsenals also reflect the gap. France and Britain combined hold roughly 500 warheads — less than a tenth of Russia’s 5,500. Britain’s Trident missiles are U.S.-maintained. France has no tactical nuclear weapons by design: Paris rejects the concept of a limited nuclear war on European soil.

At a meeting of Europe’s five biggest defense spenders in Kraków on Friday, German Defense Minister Boris Pistorius was direct. “The nuclear deterrence is achieved and will be provided by the United States, at least for the foreseeable future,” he said. “I don’t believe the world becomes a safer and more peaceful place with even more nuclear weapons in Europe.”

If the U.S. withdraws, Europe faces three options: rely on the Franco-British deterrent, risk individual countries going nuclear or build a genuinely multinational deterrent. Nicoli argues only the third would be credible — a submarine-based force with no single national veto. “The only real way to assure the response is certain is to de-territorialize the deterrent itself.” His report puts the minimum cost at 50 billion euros, with a construction timeline measured in decades and a requirement that European states pool sovereignty over the most consequential decision a government can make. No such institution exists.

A major European nuclear study group warned this week that the danger isn’t a dramatic U.S. withdrawal from NATO but something subtler: a deterrence gap that “would not emerge overnight,” but “would develop through hesitation, complacency and failure to prepare.” In January, Russia hit the Ukrainian city of Lviv with an Oreshnik ballistic missile — a nuclear-capable weapon with a range of 3,400 miles.

The FCAS collapse adds another complication. The Munich Security Conference flagged that the program’s failure risks delaying France’s military modernization — including the carrier central to its nuclear posture. France’s airborne deterrent depends on a next-generation aircraft. That question is now open.

The drone and digital battlefield components may survive, and Germany is already eyeing a rival U.K.-Italy-Japan project. And on Friday, Europe’s five top military powers announced a joint effort to quickly develop low-cost drones given the shift in modern warfare brought about by the war in Ukraine.

“There is no political will yet to seek independence from the U.S. security umbrella,” Nicoli says. “Not to the level we need. Europeans will do it if they have absolutely no other option. But the only way that results in absolutely no other option is if the U.S. completely withdraws.”

The question Europe is circling — whether any single-country guarantee can substitute for the U.S. commitment — is one this week did not answer. It illustrated, again, why the answer is so hard to find.

Courthouse News correspondent Yuval Molina is based in Brussels, Belgium.