A senior German minister has suggested that the UK and France could play a larger role in Europe's nuclear shield if Donald Trump wins this year's US presidential election – an idea that would represent a major turning point in the continent's defence strategy.

Christian Lindner, who serves as Germany's finance minister and heads the country's Free Democratic Party, argued in his piece that the transformation of the global security order means that the continent's two nuclear powers may have a far greater role to play if they are prepared to step up.

"The strategic nuclear forces of France and Great Britain are already making a contribution to the security of our alliance," Lindner wrote. "The French president, Emmanuel Macron, has made various offers of cooperation. We should understand Donald Trump's recent statements as a call to further rethink this element of European security under the umbrella of NATO."

Lindner's argument comes not long after Trump gave a speech saying that he would essentially abandon NATO countries who did not meet the alliance's minimum defence spending threshold and that he would even give Russia the green light to attack them.

The UK and France have both maintained nuclear deterrents for decades, albeit with different approaches to their deployment and use. The UK's Trident system, for instance, is exclusively submarine-based, with one of the Navy's fleet of four nuclear-armed submarines deployed at any given time.

The long-range missiles the submarine carries can only be launched on the orders of the prime minister, which are contained in a letter carried on the submarine – which in turn is only to be opened by the crew if the UK itself is hit by a catastrophic attack. It is the prime minister's prerogative to order that the weapons not be fired.

France, meanwhile, maintains a submarine and air deterrent, the so-called 'Force de Dissuasion'. Its arsenal of nuclear warheads is believed to be the world's third-largest, but according to the Arms Control Association, the country's launch protocol has been deliberately slowed down and may take as long as several days.

A new German doctrine

The advent of the war in Ukraine has spurred a major shift in German defence thinking, beginning with a more assertive effort than expected to provide the Ukrainian military with ammunition and military hardware.

The move to a new security doctrine is a theme hammered home by Lindner in his op-ed.

"The turning point in German security policy has now lasted two years," he wrote. "It is becoming increasingly clear that the era following the end of the East-West conflict, which laid the foundations for Germany's security, stability and prosperity with its security policy decisions, is irrevocably over.

"One thing must be clear to us: there is no way back to the security policy paths of the past 30 years."

The defence minister, Boris Pistorius, has already called for the German army to break with decades of military doctrine and transition from a defensive force ready to contribute to multilateral peacekeeping into one ready for war.

He has also warned that Russia could attack at least one NATO country within the next five years – tallying with a leaked German "exercise scenario" laying out a scenario for a full-on Russian war in Europe in the next two years.

The plan envisions what would happen were Russia to amass troops in Belarus for an attack on one or more of the Baltic states, forcing NATO to deploy as many as 300,000 of its members' forces in eastern Europe by the start of 2025.

German finance minister: NATO's 2% spending target 'is sufficient'

Christian Lindner, Germany's Finance Minister, speaks at the Political Ash Wednesday of the FDP Brandenburg.

German Finance Minister Christian Lindner is against spending more on defence beyond NATO's target of 2% of gross domestic product (GDP).

"Given the size of the German economy, 2% of defence spending is sufficient. We must decide over the next years, but maintaining 2% is already challenging," Lindner told a panel discussion before the official opening of the Munich Security Conference on Friday.

Lindner said that the target would become harder for Berlin to meet from 2028, when the a one-off rearmament programme worth €100 billion ($107 billion) to upgrade the Bundeswehr expires.

The finance minister reiterated his desire to see Germany stick to its traditional fiscal discipline. He said the need to make military improvements in Europe was no reason for debt-fuelled spending.

He spoke out in favour of a single market in the EU for defence manufacturers and joint procurement, but said that economic growth was ultimately the key to enhancing defence capabilities.

He said it had become "a sport" in Brussels lately to see the answer to every problem in joint EU borrowing.

Trump threats spark new nuclear arms debate in Germany

A senior member of German Chancellor Olaf Scholz's party, Katarina Barley, said the issue of nuclear arms may need to be discussed.

Two years after its about-turn on defence policy in response to the Russian invasion of Ukraine, Germany is starting to rethink another national taboo: nuclear weapons.

Previously reluctant to engage in foreign military commitments following World War Two, Germany changed course after Russia's 2022 invasion, becoming one of the biggest contributors of weapons to Ukraine.

Now German officials are openly raising the question of nuclear weapons, prompted by recent comments about NATO from Donald Trump, a likely contender in this year's US presidential vote.

Trump's suggestion that the United States should abandon any NATO ally that did not meet the alliance's defence spending target has shaken officials in Berlin, which has long looked to Washington for protection.

The nuclear arms "issue" might need to be discussed, Katarina Barley, the lead candidate for Chancellor Olaf Scholz's Social Democrats at the European Parliament elections, told the Tagesspiegel daily on Tuesday.

Barley's speculative words have sparked a debate on the ultimate deterrent in Germany, where anti-nuclear and pacifist politics are deeply rooted in society.

Already, the war in Ukraine has pushed others towards reconsidering the need for Germany to have a nuclear deterrent -- even an indirect one.

Joschka Fischer, a former foreign minister from the Greens, came out in favour of a joint European deterrent in December.

"Should the Federal Republic (of Germany) have nuclear weapons? No. Should Europe? Yes," said Fischer, whose party has had close ties to the anti-nuclear movement since its founding.

- Shifting debate -

The idea has been considered by senior figures within the government, too.

In an article for the Frankfurter Allgemeine Zeitung newspaper, Finance Minister Christian Lindner said it was time to think about a European bomb in cooperation with the continent's two nuclear powers, France and Britain.

"Under what political and financial conditions would Paris and London be ready to maintain or expand their own strategic capabilities for collective security? And vice versa, what contribution are we (Germany) willing to make?" Lindner said.

Successive German governments have seen little alternative to the transatlantic partnership with the United States and have rebuffed moves by other countries -- usually France -- to strengthen European sovereign defence.

"I do not see what the point of this discussion now is," Scholz said in December, when asked about a European bomb.

All the same, "the lines have moved" on the issue, said Markus Kaim, researcher at the German Institute for International and Security Affairs (SWP).

"Ten years ago there was a Berlin consensus that nuclear weapons were unnecessary," Kaim said.

"Now the question is how we organise (nuclear deterrence)," he said, adding that such a project still faced major hurdles.

"The European Union would have the money and the know-how, but as long as there is no 'United States of Europe', the model cannot work," Kaim said.

- 'Far away' -

Who would have the codes for launching a European bomb, the head of the Commission in Brussels or one or all of the 27 capitals?

A joint deterrent "requires a massive integration step by the EU, which we are still very far away from", said Lydia Wachs, a researcher on international relations at Stockholm University.

Relying on just one member state -- France again -- would prove similarly difficult.

In 2020, French President Emmanuel Macron put forward a "strategic dialogue" to other European countries on the "role of the French nuclear deterrent for our collective security".

But opening a nuclear umbrella from Paris to cover the rest of Europe was "highly unrealistic from both a political and military-technical perspective", said Wachs.

France would have to "massively expand and rebuild its nuclear arsenal and change its strategy", a process which would take massive time and investment, she said.

For the German daily Handelsblatt, the chilling logic of nuclear deterrence was however one Germany could no longer afford to ignore.

"Hoping that (US President Joe) Biden will win the election or that things will not be so bad under Trump seems like a comfortable strategy, but also a very risky one," it said.