As European leaders meet in Paris to prepare an answer to their apparent exclusion from the talks about Ukraine’s future, the existential and all encompassing question of how to influence an unchained US president occupies every European leader.

The Finnish president, Alexander Stubb, speaking at the Munich Security Conference, offered some Nordic advice. “We Finns in these situations are cool, calm and collected so what we do first is have an ice bath and after that we go to the sauna and then we reflect.” Faced by what he described as a “cacophony” of het-up and shocked diplomacy, he suggested: “We need to talk less and do more.”

His Latvian counterpart, Edgars Rinkēvičs, meanwhile admitted such discussions about Europe’s relationship with the US resembled psychological counselling. He said he was worried that part of European culture just may not be attractive to modern America: “We try to reflect and look for the perfect solution. We are very process oriented, and not results oriented”.

The new prime minister of Iceland, Kristrún Frostadóttir, urged Europe to try to calm things down. “There is a lot of hot air and not much clarity about what the US is saying and what it is expecting. Let’s make sure we are not reacting to the wrong things,” he said. “We cannot do without the Americans. They are throwing things a bit up in the air, but it is our responsibility to catch them, to bring them down and not to keep them in the air.”

Easier said than done. When the US vice-president, JD Vance, visits Dachau concentration camp and then delivers a message that in effect endorses Alternative für Deutschland days before Germany goes to the polls, it is hard for most Germans to think America is truly in listening mode as its officials privately reassure.

The Breitbart-style portrait of Europe with kommissars, dissidents locked up, elections rigged and censorship rife appeared deluded to the security establishment in the audience. To be told Europe’s true enemy lies within, and it is you, was – as the German defence minister Boris Pistorius let rip in his response – well, unacceptable.

Indeed, the consensus that emerged from Munich and its preceding days was Trump 2.0 is a far more disruptive and chaotic force than the worst fears of British, European and Middle Eastern diplomats. Abrupt and inchoate decisions in foreign policy follow one executive order after another. Sir Alex Younger, a former head of M16, argued Trump had ushered in a rules-free amoral world order in which the only commodity that mattered was raw power. “We have moved from a world of rules and multilateral institutions to strongmen making deals over the heads of weaker, and smaller countries,” he said. “This is our new world. This is Donald Trump’s world. The key psychological pivot we have to make is to that world. We are not operating in a systems world any longer, but an incentives world.”

But Munich showed there were two fundamental points of European disagreement – whether the rupture with America was recoverable, and what Vladimir Putin ultimately wanted, a subject that preoccupies Europe as much as discerning what Trump wants, apart from providing his own 24-hour rolling news service. The Ukrainian president, Volodymyr Zelenskyy, was not far wrong in saying Putin’s shadow was in every conversation in Munich. “The most influential member of Nato seems to be Vladimir Putin right now,” he joked.

One school of thought on the US, as articulated by Stubb, argues that Trump would take notice if the EU finally does what it has so long promised to do and boosts defence spending. “We need to take more responsibility, hike up defence spending and think how Europe can give value added to the US,” he said.

On the other hand, Nathalie Tocci, the head of the Italian thinktank IAI, questioned whether something more profound was under way between Europe and the US. “One interpretation about what has happened in the last few days is that maybe this US administration does not quite like us very much, and maybe if we act by spending more on defence, and all the rest of it, we can somehow rekindle US interest and perhaps even US affection for Europe, including Ukraine. That is the best case scenario,” she said.

“But should we not consider there is a scenario out there, in which there is absolutely nothing we can do to rekindle that love, affection and interest, and therefore we are alone, facing a US administration that deliberately wants to weaken and divide us?”

Friedrich Merz, Germany’s likely next chancellor after elections this month, did not go as far as Tocci, but accepted the Vance speech had broadened the points of issue between Europe and the US. “Disagreements between the US and Europe have taken on a completely new quality,” he said in his weekly email to supporters.

“It is now about our fundamental understanding of democracy and open society. It is now about the independence of the courts and the separation of powers and about the basic consensus to date regarding the actual threats to our freedom.”

Robert Habeck, the German Green vice-chancellor, also felt something fundamental had changed. The US government had “rhetorically and politically sided with the autocrats”, he said. Over the course of the weekend in Munich, “the western community of values was terminated here”. He added: “One thing has to be made clear: this is not conservatism, or what conservatism used to mean. This is authoritarian-revolutionary.”

Yet for most Europeans it is still best to see if a loveless marriage can be salvaged: the alternatives of a trial separation, let alone full divorce, are too frightening to contemplate. Europe is not ready to be alone, with a US nuclear umbrella. So the focus that got lost in the angst is instead on a major boost to European defence spending, not only because it would eventually make Europe more independent from the US, but because it may yet persuade Trump not to leave the security of Europe and Ukraine in the lurch.

In his speech to the Munich conference, the current German chancellor, Olaf Scholz, predicted that any future chancellor would exempt defence and security spending from the debt brake enshrined in the German constitution. “If a war in the middle of Europe was not an emergency”, he questioned what was.

Similarly the European Commission president, Ursula von der Leyen, promised Trump the EU would offer a bold new approach on defence spending that would “amount to moving mountains”. The rise in EU defence spending from €200bn (£167bn) before the start of the Ukraine war to €320bn last year would not just have to continue, but accelerate. If EU spending could be increased from 2% to 3% of GDP, hundreds of billions of investment would be unlocked. By activating the escape clause for investments, a way of excluding most defence spending from EU debt rules, a transformation could be achieved.

But a promise to increase defence spending within a year does not deal with the here and now, and the demands of US officials who say they are working on Trump time – which requires a solution to everything tomorrow. Trump is about to press Europe on whether it has the resources to provide Ukraine with a credible security guarantee. “Finding a European sui generis model is hard since what the Europeans can provide ad hoc would not offer credible protection,” Claudia Major, a German security expert, wrote in a working paper for SWP (German Institute for International and Security Affairs) in January. An EU deployment of this kind would only be possible with recourse to forces already included in Nato defence planning and Nato’s “strategic enablers”.

The EU has not yet carried out such a robust operation on this scale. Without US participation, such a mission would not be credible. What would be needed to deter a country would be an “additional western ideal contingent strength of around 150,000 soldiers”. Major concludes: “A ‘bluff and pray’ approach that uses too few troops and is essentially based on the hope that Russia will not test it would be negligent and increases the likelihood of war in Europe.”

It gets more sobering. She continues: “Based on the strength of the Russian armed forces deployed in Ukraine (approximately 600,000-700,000), and taking into account the Ukrainian armed forces (more than 100 brigades), the ideal additional western contingent strength required would be around 150,000 soldiers. As these forces would be on permanent standby, there would be a need to rotate them. This would effectively triple the force requirement.” In that context whatever offer Keir Starmer makes in terms of the British army is going to have to be enormous.

It may still require US cooperation, an open question. Major writes: “A mission entirely without US support is inconceivable because of the mix of capabilities required for such an endeavour. US capabilities in the areas of air patrol, air and missile defence, and [command and control] in general, remain key capabilities and an indispensable prerequisite for the deployment of allied forces. While most, if not all, US operations could be conducted remotely without requiring a large US military footprint in Ukraine, a US military presence would significantly reinforce the deterrence message.”

The French counter that the envisaged mission is not a frontline ceasefire enforcement role, but more one of reassurance over the battlefield horizon. But Major warns: “Providing too few troops, or tripwire forces without reinforcements, would amount to a bluff that could invite Russia to test the waters. There would be little Nato could do about it.”

But that leads to the second of Europe’s concerns – Putin’s true intentions Many Europeans see Russia’s assault on Ukraine as a war of colonial aggression, and part of an undisguised revived Russian imperialism. After he has gobbled up four Ukrainian oblasts, he may rest for two years, but he will back for more, and a broader message will be sent to the authoritarians waiting in the wings.

Radosław Sikorski, the Polish foreign minister, argues that the credibility of the US is on the line as to how this war ends: “If you allow Putin to vassalise Ukraine that will send a message to China that you can recover what you regard as a renegade province and that would have direct consequences for US grand strategy, for the US system of alliances and possibly for the future of Taiwan.”

So what to do? Sikorksi had an ingenious solution. To remind Trump “we Europeans control the Nobel peace prize. If you want to earn it, a peace has to be fair.”