House Republican leaders, facing a revolt among conservatives and moderates in their ranks, pulled legislation to repeal the Affordable Care Act from consideration on the House floor Friday afternoon in a humiliating defeat for President Trump on the first legislative showdown of his presidency.

Paul D. Ryan, the House speaker, rushed to the White House shortly after noon to tell Mr. Trump he did not have the votes for a repeal bill that had been promised for seven years — since the day President Barack Obama signed his landmark health care act into law.

Mr. Trump, in a telephone interview moments after the bill was pulled, blamed Democrats and predicted that they would seek a deal within a year after, he asserted, “Obamacare explodes” because of higher premiums. The president said he did not fault Mr. Ryan and said that he was pleased to move past his first legislative fight. He maintained that he was merely going along with the House bill.

But the effort to win passage was hardly kept secret. Vice President Mike Pence and Tom Price, the health secretary, rushed to Capitol Hill for a late appeal to House conservatives, but their pleas fell on deaf ears.

“You can’t pretend and say this is a win for us,” said Representative Mark Walker, Republican of North Carolina, who conceded it was a “good moment” for Democrats.

“Probably that champagne that wasn’t popped back in November may be utilized this evening,” he said.

House Speaker Paul D. Ryan walked in the Capitol on Friday after a vote on the rules for debating the American Health Care Act, the bill to replace the Affordable Care Act known as Obamacare.

At 3:30 p.m., Mr. Ryan called Republicans into a closed-door meeting to deliver the news that the bill would be pulled, with no plans to try again. The meeting lasted five minutes.

“We’re going to go home and spend time with our families and time with our constituents, and one day I hope we can eventually repeal,” said Representative Chuck Fleischmann, Republican of Tennessee.

The Republican bill would have replaced the Affordable Care Act, known informally as Obamacare, which mandated that almost everyone have health insurance, with a system of age-based tax credits to purchase health insurance plans.

But it never won over conservatives who wanted a far more thorough eradication of the Affordable Care Act. Nor did it have the backing of more moderate Republicans who were anxiously aware of the Congressional Budget Office’s assessment that the bill would leave 24 million more Americans without insurance.

With the House’s most hard-line conservatives holding fast against it, the bill’s support collapsed Friday after more rank-and-file Republicans came out in opposition, including Representatives Rodney Frelinghuysen of New Jersey, the soft-spoken chairman of the House Appropriations Committee, and Barbara Comstock of Virginia, whose suburban Washington district went handily for the Democrat nominee, Hillary Clinton, in November.

“Seven years after enactment of Obamacare, I wanted to support legislation that made positive changes to rescue health care in America,” Mr. Frelinghuysen wrote in a statement. “Unfortunately, the legislation before the House today is currently unacceptable as it would place significant new costs and barriers to care on my constituents in New Jersey.”

NEW YORK TIMES