Donald Trump has told the Davos economic forum “without us, most countries would not even work”, but for the first time in decades, many western leaders have come to the opposite conclusion: they will function better without the US.

Individually and collectively, they have decided “to live in truth” – the phrase used by the Czech dissident Vaclav Havel and referenced by the Canadian prime minister, Mark Carney, in his widely praised speech at Davos on Tuesday. They will no longer pretend the US is a reliable ally, or even that the old western alliance exists.

Donald Trump half withdrew his threat to invade Greenland in an unnervingly rambling speech at Davos. Photograph: Laurent Gilliéron/Reuters

Trump’s threat to invade Greenland – half-withdrawn in his unnervingly rambling Davos speech on Wednesday – and his glorification of the use of tariffs to intimidate his allies have been the final straw. As such – on the first anniversary of his second term – the taboos around denying him the role of “leader of the free world” seem to have been broken.

Just as the greengrocer in Havel’s story took down the sign in the shop window praising the communist empire and started to tell the truth about the sham in which he had been living, so leaders of some of the west’s liberal middle powers appear intent on shedding the collective lie about the continued value of a partnership with the US. Whether this collective discovery of backbone is more than rhetorical, time will tell.

Carney, perhaps the most articulate of those giving voice to this sentiment, vowed he would no longer live in a state of nostalgia, waiting for an old world to return. This is rupture not a transition, he said. Without once mentioning the US, he marked “the end of a pleasant fiction and the beginning of a brutal reality where the geopolitics of the great powers is subject to no constraints”.

The former governor of the Bank of England was far from alone in his diagnosis that the old, deeply imperfect rules-based order has been trampled underfoot by Trump. Speaking to the European parliament on Wednesday, the European Commission’s president, Ursula von der Leyen, said: “We now live in a world defined by raw power, whether economic or military, technological or geopolitical. In an increasingly lawless world, Europe needs its own levers of power.”

Finland’s president, Alexander Stubb, attends Davos. Photograph: Denis Balibouse/Reuters

The French president, Emmanuel Macron, repeatedly belittled and mocked by Trump this week, was at his most frank: the world is heading towards a “rule-free” system, where imperialist ambitions weigh heavily on multilateralism; the international bodies that once served to resolve problems are weakened, even abandoned; the US “is openly seeking to weaken and subordinate Europe”, he said.

The Finnish president, Alexander Stubb, the author of a book entitled The Triangle of Power: Rebalancing the New World Order, argued that liberal Europe was being squeezed twice over by the US because Washington no longer regards Europe as important in the hierarchy of US interests and because it is seen as a woke, ideological enemy.

Stubb said: “The people around Trump in the Maga movement see themselves as leading a big shift in the same way that Ronald Reagan and Margaret Thatcher did after the Keynesian consensus collapsed. They are leading a movement against liberalism, globalisation and interdependence.”

The leader most reluctant to join this public confessional was the dogmatically pragmatic Keir Starmer. Without mentioning the UK, Carney sent a message to Starmer about the flaws in his position. “When we only negotiate bilaterally with a hegemon,” he said, “we negotiate from weakness.” This is not sovereignty, he added, and the only choice for “in-between” countries was to compete with one another for favour or combine “to create a third path with impact”.

It was notable that Ed Miliband, the UK’s energy secretary, made a point of praising Carney’s speech, saying “the situation has changed” between Starmer and the US. His remarks reflect the growing division inside the Labour leadership about the need not just to voice differences with Trump but to join with others in challenging the whole ideology.

Mark Carney sent a message to Keir Starmer about the flaws in the position of ‘in-between countries’. Photograph: Arnd Wiegmann/Reuters

Wedded to the US because of the nuclear and security relationship, British diplomats have only seen the negatives in a rift with its indispensable ally. But Starmer has over the past year started to see the benefits in investing in a network of middle-power alliances to withstand the behemoths of China, Russia and the US.

Starmer’s allies say the obvious place for him to take this is by engaging with Macron to reopen the stalled talks on a closer defence alliance with Europe, including access to the European defence industry. Those talks fell apart over the high entry fee into that market demanded by the EU.

So many European powers now share a common diagnosis that the US’s values-based realism requires Europe and the UK to work more closely than ever.

That requires taking the world as it is, and not as one would like it to be, one of Stubb’s favourite phrases. It means trying, if possible, to find points of agreement with the US on Greenland through a possible permanent Nato presence, and on Ukraine through security guarantees. What can be salvaged from the relationship should be salvaged.

It does not mean giving gratuitous offence, but it does mean, like Havel’s greengrocer, “naming reality”. As Carney counselled his fellow leaders: *“*When middle powers criticise economic intimidation from one direction but stay silent when it comes from another, we are keeping the sign in the window.”

For Starmer this would be a huge wrench, breaking with 80 years of foreign policy. It may be that Trump has left him no choice.