Rep. Bradley Byrne, who planned to vote for the legislation, said that Friday would have been the "first big vote in the presidency of Donald Trump. I think it's a statement, not just about him and the administration, but about the Republican Party and where we're headed."
"So much about political power is about perception. And if the perception is that you can't get your first big initiative done, then that hurts the perceptions down the road about your ability to get other big things done," Byrne said in an interview before the decision.
The decision came hours after Ryan visited the White House to warn Trump that despite days of intense negotiations and sales pitches to sceptical members, the legislation lacked the votes to pass.
Trump had personally lobbied 120 lawmakers, either in person or on the phone, White House press secretary Sean Spicer reminded reporters on Friday. The president had "left everything on the field," Spicer said.
Spicer said that no matter what happens, the White House did not think that defeat would slow other parts of Trump's agenda including tax reform and immigration reform.
Vice-President Pence, White House Chief of Staff Reince Priebus and Health and Human Services Secretary Tom Price also made a last-ditch attempt to win over members of the hardline House Freedom Caucus, huddling with them at midday at the Capitol Hill Club, a GOP social hall next door to the headquarters of the Republican National Committee. All three exited the meeting quickly without taking questions.
In one stunning defection Friday, House Appropriations Committee Chairman Rodney Frelinghuysen announced that the health care bill is "currently unacceptable" and that changes made late Thursday to placate conservatives "raise serious coverage and cost issues."
Another moderate, Rep. David Joyce - who had met with Trump on Wednesday - said he would vote against the bill. So did Rep. Barbara Comstock, a long-time Ryan friend and ally who represents a competitive Northern Virginia congressional district.
Rep. Paul Gosar , a Freedom Caucus member, was one of six Republicans who voted against a procedural resolution bringing the bill to the floor on Friday morning.
"You know what? I came here to do health care right," said Gosar, a dentist. "This is one chance we that can get one-sixth of our GDP done right. It starts with here."
At the heart of the argument made by GOP leaders to sceptical members: Keeping the Affordable Care Act is a worse outcome than passing a potentially flawed replacement.
"You want to score a touchdown, but sometimes, on the fourth down, you kick a field goal," said Rep. Joe Barton, the longest serving member of Congress in the Freedom Caucus. "The choice is yes or no I'm not going to vote no and keep Obamacare. That'd be a stupid damn vote."
At the White House on Friday morning, Trump projected confidence as he answered shouted questions following an announcement of a presidential permit for the Keystone XL pipeline, a revived project that the president said would create jobs.
Asked by a reporter what he would do if the bill fails, Trump - seated at his Oval Office desk - shrugged and said: "We'll see what happens."
Trump also said he didn't feel the process had been rushed and that Ryan should remain as speaker if the bill fails.
On Twitter, Trump said that "After seven horrible years of ObamaCare (skyrocketing premiums & deductibles, bad healthcare), this is finally your chance for a great plan!"
