US Senators have rejected a measure to repeal parts of former president Barack Obama's healthcare law, dealing a serious blow to President Donald Trump's agenda.
As they were unable to pass even a "skinny repeal", it is unclear whether Senate Republicans can advance any health bill despite seven years of promises to repeal "Obamacare".
"This is clearly a disappointing moment," majority leader Mitch McConnell said.
"I regret that our efforts were not enough, this time. It's time to move on."
Mr McConnell put the health bill on hold and announced that the Senate would move on to other legislation next week.
Mr Trump responded on Twitter, saying the Senators who voted against it had "let the American people down".
A key vote to defeat the measure was cast by Arizona Senator John McCain, who returned to the Senate this week after receiving a diagnosis of brain cancer.
In an impassioned speech on the day he returned, he had called for bipartisanship on major issues of national concern, and a return to the "regular order" of legislating by committee.
Three Republicans joined with all Democrats to reject the amendment, which would have repealed a mandate that most individuals get health insurance and suspended a requirement that large companies provide coverage to their employees.
What parts of Obamacare would change with a "skinny repeal"?
- The unpopular Affordable Care Act requirement that most people have health insurance or risk a fine would be repealed
- A similar requirement for large employers would be suspended for eight years
- Funding to Planned Parenthood would be denied for a year
- A tax on medical device manufacturers would be suspended for three years
The final vote was 49-51. Republicans Lisa Murkowski of Alaska and Susan Collins of Maine joined McCain in voting no.
The amendment was a last resort for Senate Republicans to pass something to trigger negotiations with the House.
The failure comes during a tense time for the White House, with internal bickering spilling out into the public after newly-appointed communications director Anthony Scaramucci held an expletive-laden phone call with a reporter.
Less than a week after starting his role, Mr Scaramucci launched an attack on two senior members of the administration - chief of staff Reince Priebus and chief strategist Stephen Bannon - in the conversation.
Mr Scaramucci accused Mr Priebus of leaking information to The New Yorker reporter and attacked Mr Bannon, one of President Trump's top advisors, for apparently courting media attention.
Mr Scaramucci posted a tweet after The New Yorker article was published, saying he sometimes used "colourful language" but that he would "not give up the passionate fight for @RealDonaldTrump’s agenda".