(Sarah Parnass/The Washington Post)

Congress took its first step toward rolling back President Obama’s health-care reform law Friday, with the House voting along party lines to pass a crucial precursor to the Affordable Care Act’s unraveling.

It will now only get harder for Republicans. They must assemble a viable replacement for a law that has expanded health insurance coverage to roughly 20 million Americans and eliminated unpopular insurance industry practices, such as lifetime coverage caps and widespread refusal to cover already-sick individuals.

Republican leaders have instead focused on the Affordable Care Act’s flaws — rising premiums for plans sold in state marketplaces, high deductibles and burdensome taxes. GOP lawmakers are set to gather in Philadelphia later this month to hash out a more complete alternative.

House Speaker Paul D. Ryan (R-Wis.) said Friday’s nearly party-line vote would launch a “thoughtful, step-by-step process” that would include action by both Congress and the Trump administration.

“This is a critical first step toward delivering relief to Americans who are struggling under this law,” he said. “Our goal is a truly patient-centered system, which means more options to choose from, lower costs and greater control over your coverage. And as we work to get there, we will make sure that there is a stable transition period so that people don’t have the rug pulled out from under them.”

(Alice Li/The Washington Post)

The final vote was 227 to 198, with nine Republicans joining all the Democrats in voting no.

The budget measure, which was passed Thursday by the Senate, paves the way for Republicans to use special budget procedures to repeal major parts of the law without cooperation from Democrats.

House Republicans from divergent wings of the party raised concerns this week about taking that initial step without having a more detailed plan in place for ultimately replacing Obamacare.

House leaders worked to address those concerns, even as President-elect Donald Trump made public statements setting out an ambitious timeline for action that many lawmakers see as unrealistic.

During a nationally televised town hall meeting Thursday, Ryan said Congress would act “definitely within these first 100 days” on a replacement plan.

Rep. Cathy McMorris Rogers (R-Wash.), House Speaker Paul D. Ryan (R-Wis.), and Vice President-elect Mike Pence listen to House Majority Whip Steve Scalise (R-La.) during a Jan. 4 Republican press conference on Capitol Hill. House GOP lawmakers were set to vote Friday to start the process of rolling back the Affordable Care Act. (Melina Mara/The Washington Post)

The handful of House Republicans who opposed the budget measure Friday remained wary about the path ahead. About half were moderates, half hard-line conservatives.

“I’m much more concerned about the content than the timing,” said Rep. Tom MacArthur (R-N.J.), a former insurance executive who voted no. “I think we’re going a little too fast. That said, I understand leadership’s goals and I agree with them: We have to fix what is clearly broken with Obamacare.”

A number of skeptical Republicans polled Friday said they had gotten sufficient assurances on the process ahead that they would vote yes.

One lawmaker familiar with behind-the-scenes GOP discussions said leaders pledged to hold a vote on a replacement bill alongside the ACA repeal legislation. Leaders also promised, the lawmaker said, to include in that repeal bill — which would be subject to the special budget procedures — major elements of a replacement plan.

Under those procedures, known as reconciliation, only provisions with definitive budgetary impacts can be included in the bill, so it could not be used for a complete Obamacare alternative.

“We’ve been showing more of the details, but a lot of this is going to be done in committee,” said Rep. Steve Scalise (R-La.), the majority whip. “We’re not going to be like what [Democratic leader] Nancy Pelosi did, where she wrote the bill in a backroom, dumped it on the floor and said, ‘Pass the bill to find out what’s in it.’ We’re actually going to have our committees write the bill in open hearings. I think that’s going to be refreshing.”

Pelosi (D-Calif.), who as House speaker muscled the Obamacare legislation through in 2009 and 2010, is now leading the opposition to its repeal as minority leader.

On the House floor Friday, she dismissed the “mythology” surrounding the ACA — which did, in fact, move through congressional committees, though without GOP cooperation — and accused Republicans of “feeding their ideological obsession with repealing the ACA and dismantling the health and economic security of hard-working families” without coming up with a workable alternative.

“They talk about repeal and replacing,” Pelosi said. “For six years, they have had a chance to propose an alternative. We see nothing.”

Budget measures such as the one under consideration Friday are typically strictly partisan affairs. Republicans hold a 24-vote advantage over Democrats in the House; if more than a handful of Republicans had balked, GOP leaders would have faced an embarrassing delay.

Republicans got a nudge this week from conservative activist groups, including the Club for Growth and Heritage Action for America, which called for the budget measure’s passage. And Trump took to Twitter to hail its passage in the Senate.

But for most rank-and-file Republicans, the choice was relatively simple: After running campaign after campaign against Obamacare, would they really pass up their first chance to unravel it?

“If there’s been one promise that Republicans have run on for the last six years, it is that we are going to do our best to repeal Obamacare,” said Rep. Mark Walker (R-N.C.), chairman of the conservative Republican Study Committee. “I think that [the congressional vote] affirms our promise today.”