Trump gave the WHO a list of demands. Hours later, he walked away.

Mr. Bremberg hand-delivered a list of seven demands that American 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 W.H.O. The announcement blindsided his own diplomats and Dr. Tedros alike.

If Mr. Trump thought Dr. Tedros would relent under the pressure of an American withdrawal, he was wrong. The W.H.O. 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 Joseph R. Biden Jr. 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 organization that even staunch supporters say is in dire need of change.