US Republicans failed spectacularly today in their latest effort to dismantle Obamacare, leaving the party shocked and in disarray and signalling the potential death knell for President Donald Trump's dream of repealing his predecessor's health reforms.
The vote - held in the dead of night - came down to the wire, with the decisive moment resting with Senator John McCain, recently diagnosed with brain cancer, who sided with two moderate Republicans and all Democrats in opposing the legislation.
"This was a disappointment, a disappointment indeed," Senate Majority Leader Mitch McConnell told colleagues after one of the most tense votes in years on the Senate floor.
"I regret that our efforts were simply not enough this time."
The collapse marks a major setback for Republican leadership and for Trump, who had campaigned relentlessly on a pledge to repeal and replace the Affordable Care Act that passed into law under his predecessor Barack Obama in 2010.
Today's vote, which capped a series of failed efforts in recent months to get an Obamacare repeal measure over the line, was on a so-called "skinny repeal" bill that would have rolled back only parts of Obamacare but kept the bulk of the law intact.
It crashed to defeat, 49-51, leaving Trump's singular legislative initiative, and Republicans' seven-year pledge to rip out the health care law, in tatters.
Trump, who had long cajoled and strong-armed Republicans in a bid to get them into line, swiftly spoke out about the failure, apparently unmoved by Democratic pleas for the parties to work together and improve the existing law.
"3 Republicans and 48 Democrats let the American people down," Trump tweeted. "As I said from the beginning, let ObamaCare implode, then deal."
Senate leadership had never intended "skinny repeal" to become law; they saw it as merely a vehicle for joining forces with House Republicans to craft a broader repeal-and-replace plan.
But some Republicans including McCain blasted the bill as terrible policy, and grew nervous that the House of Representatives might turn around and pass the bill instead of going to conference with the Senate.
The non-partisan Congressional Budget Office analysed the bill, and concluded that insurance premiums would spike by 20 percent per year and 16 million people would lose insurance if it became law.
House Speaker Paul Ryan later said his side was willing to negotiate with the Senate, but that failed to placate McCain.
Vice President Mike Pence was brought to the chamber around midnight, in case he would be needed to break a 50-50 tie.
But he never got the opportunity, as McCain, whose war hero status was mocked by Trump in 2015, refused to cave to pressure to get on board, despite extraordinary scenes on the Senate floor where a grim-faced Pence huddled with McCain for several minutes.
"We must now return to the correct way of legislating and send the bill back to committee, hold hearings, receive input from both sides of aisle, heed the recommendations of nation's governors, and produce a bill that finally delivers affordable health care for the American people," McCain said in a statement.