If next year’s G7 summit turns out to be a branding event at a Trump golf resort in Florida, with Vladimir Putin as the de facto co-chair, the old guard among America’s allies will look back on this year’s meeting in Biarritz with some nostalgia.

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Not much was achieved, truth be told, but that is nothing new. To avoid the embarrassment of the previous year in Quebec – when Trump disowned the carefully crafted joint communiqué soon after boarding Air Force One – Emmanuel Macron, the host in Biarritz, had the wheeze of doing away with the traditional statement altogether. If there was no document, there was nothing to refuse to sign.

The downside was that the meeting left little trace it had ever happened, apart from the enduring resentment of Biarritz, which was cordoned off for three days, and its residents forced to wear violet identity badges to get past the police cordons.

But at least the leaders of the world’s larger industrialised democracies – loosely described as the west – put on a show of common endeavour. They put out a “declaration” with a handful of aspiration thoughts about trade, Iran, Ukraine, Libya and Hong Kong, which was thinner than the single page it was printed on.

There were well-meaning statements on the need to prevent Iran to acquire nuclear weapons and some trade tensions were eased. A vow was also made to do something about the burning Amazon, with a combined down-payment of €20m, significantly less than the cost of the summit, and a particularly paltry sum in view of what was generally agreed to be an existential threat to the planet.

Looming over the whole affair, however, was an awareness that everything could become a lot worse next year when Trump will be the circus-master, making a fat profit on food and lodging at his golf resort outside Miami airport. He will then be in the middle of his campaign for re-election – and therefore even less engaged or willing to compromise than he was in Biarritz.

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The conceit of the G7 is that it represents a club or family of like-minded nations. Next year, they could find themselves to be more little more than Trump’s paying customers.

Fittingly, there was an end-of-epoch feel to the venue. Biarritz is old-world glamour, overlooking the Bay of Biscay, with gentle breezes and golden evening light on its neatly raked beaches. It evokes a grandeur from another age, when Europe was the centre of the world, and it could assume that its values would be at least admired if not emulated.

One by one, surrounded by their entourages, the leaders took the morning air, strolling from their quarters at the imposing Hotel du Palais, past the art deco casino where the one-armed bandits and blackjack tables were silent for the long weekend, and up a steeply rising path to the meeting rooms at the Bellevue. There sense of importance combined with their evident impotence was reminiscent of Europe’s ruling dynasties on the eve of the first world war, oblivious to the fact their world was going to end.

Boris Johnson, with his calculated dishevelled and absent-minded demeanour, came across in particular as a character actor in an Edwardian period drama, literally making his small splash by swimming out from the deserted beach to a rock with a broad opening in it, returning to declare it a metaphor for Brexit.

Facebook Twitter Pinterest Boris Johnson speaks during a news conference at the end of the G7 summit. Photograph: Dylan Martinez/Reuters

None of the cast had a sense of theatre to match the master of ceremonies, President Macron. From the start he tried to shake the dullness and sense of futility out of the proceedings with the occasional stunt. He corralled Trump immediately on the US president’s arrival, ushering him out on to the hotel terrace where an outside table had been prepared with white linen and places set for two. It was a gambit to get to the man by himself, away from his aides.

The American later declared it to have been their best meeting, but there was enough of a meeting of minds to clear the way for Macron’s second theatrical coup, flying in Iran’s foreign minister, Mohammad Javad Zarif, for talks across the road from the summit, thereby creating a buzz of anticipation of a diplomatic breakthrough between Tehran and Washington at a time when they seem to be drifting towards war.

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At the final closing conference with Trump, Macron also had a surprise, declaring himself confident that Trump could meet his Iranian counterpart Hassan Rouhani in the coming weeks. Trump, always keen for a photo op, did not rule it out. But there was no sign, as the delegations went their own way on Monday morning, that the US was prepared to take the requisite first step towards dialogue and relaxing its punishing oil embargo. Without that, the Macron initiative is doomed to remain a piece of performance hard.

Again and again, Macron’s efforts at projecting progressive modernity were belied by the turgid underlying realities. There were sessions on gender equality, but when it came for the group photo of the expanded guest list as the sun set outside the Hotel du Palais, there were 24 men on the dais, and one woman, Angela Merkel, in the twilight of her political career.

If there was a moment that sounded the death knell of the old order, it came at dinner in Biarritz’s antique lighthouse. The leaders were served Basque specialities and spoke about the pressing matters of the day.

Facebook Twitter Pinterest Emmanuel Macron and Donald Trump shake hands in Biarritz. Photograph: Ludovic Marin/AFP/Getty Images

But the mood turned sour when Trump interrupted the flow of conversation to press the case for admitting Putin back in to the club, to make it the G8 once more. The Europeans, with the exception of the Italians, were outraged. Putin had been booted out in 2014 for breaking all the rules of the postwar world, ignoring borders and annexing Crimea. Since then he has shown no sign of reversing his land grab.

Furthermore, Putin’s regime was becoming more and more repressive. Whatever hopes there might have been that he would take a turn towards economic and political form had long since dissipated.

The G7, the Europeans insisted, was a family of liberal democracies or it was nothing. Trump did not seem to care; the phrase “liberal democracy” meant nothing to him. His nominal allies were stunned by his indifference to what they held sacred and his determination to act on Putin’s behalf.

Macron passed the baton to Trump on Monday with a hug and a show of camaraderie. But there was a distinct sense of the established order being given its last rites – not to be replaced by anything fresh, but by a reversion to something even older and more visceral.

In the new order, the aspirational talk of a fairer and greener future will be dispensed with to be replaced by the pursuit of profit, and the division of the world by a handful of powerful men.