GENEVA (NYTIMES) - In late May, the US ambassador in Geneva, Mr Andrew Bremberg, went on a rescue mission to the World Health Organisation (WHO) headquarters. He told its director-general, Dr Tedros Adhanom Ghebreyesus, that despite weeks of threats that President Donald Trump would quit the health organisation, the relationship could still be salvaged.

Mr Bremberg hand-delivered a list of seven demands that US officials saw as the beginning of discreet discussions.

Hours later, Mr Trump took the lectern outside the White House and blew it all up, announcing that the United States would leave the WHO. The announcement blindsided his own diplomats and Dr Tedros alike.

If Mr Trump thought Dr Tedros would relent under the pressure of a US withdrawal, he was wrong. The WHO leader has refused to make concessions or counteroffers, according to American and Western officials. And Mr Trump ultimately made good on his promise to abandon a health agency that the United States helped form a half-century ago.

With Mr Trump's election defeat, President-elect Joe Biden appears ready to rejoin the global health body. But he will inherit a fractured relationship and must quickly make decisions about how to overhaul an organisation that even staunch supporters say is in dire need of change.

While the Trump administration's demands are now moot, they offer a glimpse into both the growing US frustration with the WHO and Mr Trump's personal grievances.

And as Mr Biden signals a return to multinational diplomacy, the Trump administration's demands offer a behind-the-scenes glimpse of the deal-making of a president who favoured aggressive, unpredictable moves over more conventional negotiations.

As has often been the case during Mr Trump's presidency, his administration was divided, current and former officials said.

Diplomats and veteran health officials said the list contained reasonable requests that might have been easily negotiated through normal channels. (The WHO has since made some changes anyway.) But it also contained politically sensitive, if not inappropriate, demands.

"It doesn't seem to reveal a clear strategic vision," said Mr Gian Luca Burci, a former counsel to the health organisation who reviewed the list for The New York Times.

Experts said it was easy to see why, in the face of Mr Trump's withdrawal and his efforts to deflect blame for the pandemic, Dr Tedros chose not to negotiate.

"It was an enormous backfire, and it was bound to be," added Professor Lawrence Gostin, a Georgetown University law expert and longtime WHO adviser who also reviewed the list. "It wasn't a negotiation. It was blackmail."

The State Department did not directly address its proposed terms but said it had acted in good faith in calling for needed changes.

"At a critical moment when the WHO leadership had the opportunity to rebuild trust among some of its critical member states, it chose a path that did the very opposite and demonstrated its lack of independence from the Chinese Communist Party," Mr Bremberg, the US ambassador in Geneva, said in a statement.

The WHO did not comment. Several current and former Mr Trump administration officials and Western diplomats spoke on condition of anonymity because they were not authorised to disclose private conversations.

The US list was the product of months of growing irritation with Dr Tedros, whom senior administration officials saw as too quick to praise China or frame the outbreak in ways favourable to Beijing. Dr Tedros, for example, announced in January that China would share biological samples with the world. But he declined to speak up when China never made good on that promise.

The WHO had also quietly acquiesced to Beijing's conditions before an international mission in February and ceded control of an investigation into the virus's origins.

Some European health officials and diplomats shared the Trump administration's concerns, officials said. But they regarded these as minor issues in the midst of a pandemic.

Mr Trump was particularly focused on the issue of travel. The WHO had a long-standing policy of unrestricted travel. As health experts began reconsidering that policy, Mr Trump became preoccupied with getting credit for having halted some travel from China to the United States in February.

By April, as Mr Trump toyed with withdrawing the United States from the WHO, two camps emerged in his administration, current and former officials said. The first group, which included Mr Trump's chief of staff Mark Meadows, wanted to leave and rally support for a health agency built around Western allies.

Others - like Mr Bremberg; Mr Alex Azar, the health secretary; and Mr Adam Boehler, head of the US International Development Finance Corp - argued that only the WHO was backed up by a global treaty. If the United States could get the health agency to make changes, they said, it made sense to stay.

By late May, the list stood at seven items. The first called for investigations into the WHO's handling of the outbreak and the source of the virus. US officials said they saw this as an easy request; more than 140 countries had already endorsed these investigations.

In July, Dr Tedros would do just that. He appointed Ms Helen Clark, the former prime minister of New Zealand, and Ms Ellen Johnson Sirleaf, the former president of Liberia, to lead an investigation into the response to the pandemic. A separate investigation into the virus's origins is slowly getting underway.

Second, the United States asked Dr Tedros to call on China to provide live virus samples and stop censoring Chinese doctors and journalists. This would have been a significant break for the WHO, which rarely criticises members. Dr Tedros has told colleagues that he sees no benefit in such criticism, especially during a pandemic.

Conceding to the Trump administration's demand would have meant allowing one country to dictate the organisation's posture toward another. But in Washington, one senior White House official recalled this as a key condition, a signal of Dr Tedros' independence.

The third item asked Dr Tedros to say that countries were right to consider travel restrictions during the pandemic - a break from the long-standing advice that limiting travel would not slow the virus but would harm economies and delay medical treatment.

The WHO had already begun to soften that stance by the time Mr Bremberg delivered the list. In April, the organisation called for "appropriate and proportionate restrictions" on domestic and international travel.

But Dr Tedros interpreted the request as demanding that he apologise to Mr Trump and say the president was right to restrict travel from China, according to public health officials and diplomats who have talked to him. Dr Tedros was wary of being drawn into the US presidential campaign, where travel restrictions were a rallying cry for the Trump campaign.

The fourth item on the list called for the WHO to dispatch a team to Taiwan to study its successful pandemic response. Taiwan is not a member of the health organisation, and Beijing, which claims the self-ruled island as its own, exerts tremendous pressure to keep the WHO from engaging with Taiwan's government.

The US requests also called for the WHO to prequalify coronavirus drugs and vaccines for use around the world once they were authorised by major regulators in the United States, Canada, Europe or Japan. That could help fast-track important treatments, but it could also have been seen as allowing the United States to influence the health organisation's drug-approval policy.

The Trump administration also asked Dr Tedros to ensure that countries like the United States that contribute heavily to the WHO are proportionally represented on the organisation's staff. And it sought support for proposed changes put forward by the Group of 7 - the United States, Germany, Japan, France, Britain, Canada and Italy. That request is moot, as the G-7 proposal has been folded into larger overhaul efforts.