Nicolas de Riviere had been working for weeks on a plan to help combat coronavirus: a resolution calling for a global ceasefire to enable governments and UN agencies including the World Health Organisation get medicines and protective gear to conflict zones all over the world.

All 15 members of the UN Security Council had agreed a text. The final sign-off had come late that evening from a senior official at the US State Department in Washington. The following morning de Riviere would put the text “under silence”, signalling to all its signatories that he considered the negotiations over. As long as no one broke that silence, the resolution would come into force at 2pm East Coast time.

That was the plan, and it was a good one. The next day, 8 May, was “a big day for all of us”, says one UN diplomat involved – the 75th anniversary of the Allied defeat of Germany in World War II.

There have been bumps along the road for that alliance in the intervening years. The cold war comes to mind. So does the serial criminality of post-Soviet Russia. Even more current, and to many more concerning, has been America’s deepening isolation under its current administration.

All the more reason why it would be a powerful act of symbolism if the Security Council could unite behind a coronavirus resolution on the day of the anniversary. It would be a sign of faith in the idea of global governance. It might even be of practical use as well.

It’s reasonable to imagine that de Riviere called his wife that night. Kareen Rispal is a diplomat too. She is France’s ambassador to Canada, and they hadn’t seen each other since the US went into lockdown on 21 March. In any case, if she didn’t wish him luck on the 7th she probably offered consolation on the 8th, because barely an hour before the deadline the United States broke silence. In a terse statement that most people involved believe was written by or for Mike Pompeo, the US Secretary of State, the administration said it could not, after all, support the resolution.

At this point more than quarter of a million people had died worldwide of Covid-19. Because of the American withdrawal, the UN body responsible for peace and security was effectively silent on the matter.

Immediate media reports said the other members of the Security Council were stunned. A month later they seem mostly weary and resigned.

“It took weeks to get there and when it happened it was maddening, because of course the Security Council should have adopted [the resolution] already,” says one European diplomat close to the process. “But the US is not seen as the power here that it used to be.”

Wrecking tactics aren’t unusual at the Security Council. Its resolutions are routinely vetoed by Russia, for example, when they touch on Syria, or by China when they touch on what it considers its internal affairs (Hong Kong, Taiwan, Xinjiang). But this was America doing the wrecking.

A former US ambassador who is now an executive at a Washington think-tank said: “The Trump administration has lost its ability to surprise me, but the emphasis it is placing on re-election is yet another example of its abdication of a global leadership role.”

The statement of 8 May did not say why the US had withdrawn its support. It didn’t have to. From the start of the negotiations the American side had objected to any mention in the text of the WHO, which, for the previous month, President Trump had been blaming for the spread of the pandemic (his argument was that the agency was too “China-centric”, had connived at Chinese obfuscation, and had thereby robbed America and the world of vital time).

China wanted a mention of the WHO, but caved. The final text referred only to “specialized health agencies”.

“Everyone thought it was done and dusted,” says Richard Gowan, chief UN-watcher at the International Crisis Group. “The diplomatic community felt quite strongly that the US had won that battle.”

But in the end another battle mattered more to the administration – to shift responsibility for a rising US covid death toll as a presidential election loomed. The possibility of concerted international action against a once-in-a-century public health crisis seemed to count for little by comparison.

A distinct world-view fed into the American decision too. It reflected Trump’s “utter disdain for multilateral action in general,” says Jeremy Youde, an expert on global health governance at the University of Minnesota. But whatever ultimately led to that decision, it has left UN supporters seething.

“We have a complete fracture in global leadership right now,” Dr David Nabarro, a veteran British advisor to the WHO, said at a Tortoise event last month. “There should be a petition of 500 million people to the world leaders saying, ‘What on earth are you doing? What on earth are you playing at? We have the biggest crisis of all time in many of our livelihoods, and you’re squabbling… Whilst about 185 [UN member states] want the UN and the WHO to lead, certain others don’t but it’s for no other reason than domestic politics. People should be going absolutely crazy about this.”

Ever since Woodrow Wilson held court at the Paris Peace Conference, the US has aspired to offer the world moral leadership and an ally against tyranny. That has been changing slowly; now it’s changing fast.

America’s dominance of the UN and its agencies – whose creation it supervised after the war – has been in decline for nearly two decades. In the past two months it has imploded. Part of the reason is the pandemic, but unlike coronavirus the implosion doesn’t feel like an accident. It makes more sense if seen as part of a decisive step back from an international role that the US has played for a century with only three serious challengers.

The first two of these challengers were Nazism and Soviet Russia. The third is China, which some believe has seized the opportunity of the pandemic to manoeuvre the US into a series of diplomatic blunders.

Before the decision to scupper the Security Council resolution, Pompeo refused to sign a joint G7 communique because it did not refer to Covid-19 as the “Wuhan virus”. On 4 May the US was a no-show at the first global virtual covid vaccines conference. On 18 May, Trump sent the WHO’s director-general a four-page letter attacking its “alarming lack of independence” from China and threatening to withdraw US funding. Eleven days later, as the US death toll from the virus passed 100,000, he followed through on the threat. The only global health body of its kind is now $1.3 billion short when its role has arguably never been more vital.

“The Chinese have played this quite smartly, nudging the US into a position in which they would end up looking bad,” says Richard Gowan. But if so, there is little sign Trump cares. On the contrary, his calculation is that demonising the WHO will play well with voters in November just as demonising his opponent did in 2016.

For anyone still in doubt, America’s foreign policy doctrine under present management has become a narrow, personal thing compared with its forebears. Gone is the enlightened self-interest that made deep American commitment to Nato and the G7 and G20 as well as the UN a no-brainer despite its cost. Now it’s not even America First – alarming as that sounded when articulated from the Capitol steps in a defiant inauguration speech three years ago. It’s Trump First.

Worrying about American leadership isn’t new. George Kennan’s Long Telegram of 1946 was a timely warning about Soviet ambition. Cold War alarums over bomber gaps and Sputnik were a mixture of hysteria and defence industry self-interest, but they served the same purpose: a self-administered kick in the rear to heave the US back into invincibility.

Leading the free world became vastly more complicated after the Soviet collapse. Francis Fukuyama’s triumphalist case for liberal democracy in The End of History and the Last Man was quickly shown to be naive. The new rivalries, beneath a sheen of business class homogeneity, were economic rather than strategic. The new moral arguments were blurred, not binary.

Twelve years ago – and five years into the Iraq fiasco – Fareed Zakaria wrote wistfully in The Post-American World of a time when his adopted country seemed to know intuitively how to channel its great strength with confidence and generosity. The Marshall Plan for Europe’s post-war reconstruction, worth $100 billion in 2008 dollars, went from drawing board to building site with few strings attached. It served as a foundation stone for the trans-atlantic alliance that was tested to destruction in Iraq. The war there, Zakaria argued, left anti-American feeling at an all-time high.

Barack Obama worked to reboot American leadership, but the literature on America’s decline kept growing. (Is the American Century Over?, asked Harvard’s Joseph Nye, hoping the answer was no. That Used To Be US, wrote Tom Friedman and Michael Mandelbaum. Subtitle: How America fell behind in the world it invented, and how we can come back.)

And then came Trump. Last year, before Covid reversed every economic indicator and upended every political assumption, retired general and former Secretary of State Colin Powell ventured that American foreign policy under Trump was already “a shambles”.

Most people paying even passing attention to the president’s cavorting with dictators and impatience with old allies would have agreed. But Powell was in an especially good position to know. He had lived through reference points that others only read about.

It was Powell who told the UN in 2003 – falsely – that Saddam Hussein possessed weapons of mass destruction. And it was Powell, the year before, who rode to the rescue of the goats of Perejil Island.

Perejil Island is worth a detour; bear with me. It’s a 23-hectare lump off northern Morocco, uninhabited except for the goats. For Spain and Morocco it is disputed territory, so when Morocco sent 12 soldiers there in July 2002, Spain sent 75 to kick them off.

It fell to Powell to mediate this ridiculous dispute. He had never heard of Perejil Island and the US had no interests there, but neither the UN nor the EU had anything like the leverage of the world’s sole hyperpower. Over the course of one weekend, America’s top diplomat drafted an agreement, sent it to Madrid and Rabat from his home fax machine and put the row to bed.

That America was truly the indispensable nation. Now China is doing its utmost to make the US look dispensable.

The day of Trump’s first threat to defund the WHO was also the day of the organisation’s annual general meeting, the World Health Assembly. For the first time in 73 years the US did not attend. In its absence, China’s President Xi Jinping was first to speak. He came to the Zoom screen with an offer of $2 billion for global health initiatives over the next two years. He also promised that any Covid vaccine would be “a global public good” – which was the right thing to say, but also smart messaging given worries that the Trump administration’s Operation Warp Speed will turn out to be an America First vaccine strategy.

“The US has traditionally been the leader in this space, and to the extent that it withdraws, it creates opportunities for others,” says Jeremy Youde. “If you leave, China’s going to fill that space.”

So is it that easy? If you want to lead the world you just wait for the hegemon to sulk and pounce with a fat wallet? If so, China would be the toast of United Nations Plaza by now, and China isn’t.

This is the China gearing up to crush Hong Kong’s democracy. It’s the China where the virus originated and where most UN members – not just the US – want a full and transparent investigation into how long officials sat on crucial information about its early spread.

It’s the China that has unquestionably become more assertive in its dealings with the WHO since the 2003 SARS epidemic, and not necessarily in a good way. It has learned at least one lesson from SARS, Mara Pillinger of the O’Neill Institute for National and Global Health Law told the Washington Post in February. “They’re cooperating with WHO just enough to stave off accusations that they’re not cooperating.”

This was that sort of comment that emboldened Pompeo and Trump to turn the WHO into a bogeyman rather than support it, even if that meant distorting its role. In April, for example, Pompeo said he expected the WHO to use its “enormous authority” to force China to comply with its rules on cooperation and disclosure.

In reality it has no such authority. The organization operates under what are known as the International Health Regulations 2005, which give it no enforcement powers at all.

“The WHO can’t fine and it can’t threaten to invade,” Youde says. “So if you are saying it needs to be able to go in and get information a government is trying to withhold, you are saying you want a different sort of WHO, better funded and with more powers. And I see little evidence of the Trump administration wanting that.”

The truth is that for the sake of re-election the White House has burned a 73-year relationship with the organisation that defeated smallpox, polio and ebola. As Professor Anthony Costello of University College, London has said of the WHO, “it’s always been a useful scapegoat for politicians”.

The US mission to the UN occupies one of the most valuable pieces of real estate in the federal government’s portfolio. It’s a curvy steel and glass structure directly opposite the giant UN headquarters building in Manhattan, a block from the East River (and two down from from the Trump World Tower). “Walk out the door,” says Gordon Gray, former US ambassador to Tunisia, “and you are engaged in diplomacy”.

That’s the idea, at any rate. Representatives from all 193 UN member states are within a short walk. The round table of the Security Council, where Adlai Stevenson faced down Valerian Zorin at the height of the Cuban Missile Crisis, is across the street on level 2. You don’t even have to take the lift.

The first US ambassador to the UN was Edward Stettinius Jr., former wartime Secretary of State to Presidents Roosevelt and Truman. Unlike many plum American diplomatic posts, this one has traditionally been filled by real diplomats or at least serious political operators.

Trump ended that. His first appointee to the post was Nikki Haley, the former Republican governor of South Carolina, who proved a formidable presence including in her opposition to Trump’s so-called Muslim travel ban. She had a seat in cabinet in Washington. When she resigned two years ago she was replaced by Kelly Craft, who doesn’t.

Craft doesn’t command much respect in New York either. She and her husband, Joe Craft III (a Kentucky coal magnate with an estimated net worth of $1.4 billion) are philanthropists and generous donors to the political campaigns of Trump and Mitch McConnell, their local senator. Analysts and fellow diplomats describe her as “decent” and “collegial” but say that during the recent Security Council negotiations she was merely “following orders”.

She was at home in Kentucky throughout those negotiations, as lockdown helped to sabotage precisely the sort of diplomacy the pandemic required – the pull-asides and quiet coffees at which people with different national interests but a shared belief in global governance work out what can be read between the lines.

The White House sabotaged it too, because Trump recoils from the idea of consensus. This is not his type of deal. In the end, Robert Gowan says, the administration used the efforts of Nicolas de Riviere “as a backchannel to needle China”. It was a backchannel that backfired diplomatically but may yet yield something politically in the defensive American hinterland where team Trump is searching for new ways to divide and conquer, and to beat Joe Biden in November.

“You have to be an optimist to be a diplomat,” says Gray. “As a country we’ve shot ourselves in the foot but I think if Biden is elected president the damage will not be irreparable. If President Trump is re-elected then I’m far more pessimistic. Presumably people will forgive Americans once, but twice is not an aberration. It would be indicative of how Americans see their place in the world.”