From left, House Majority Leader Kevin McCarthy (R-Calif.), House Speaker Paul D. Ryan (R-Wis.) and Rep. Greg Walden (R-Ore.) hold a news conference on the American Health Care Act on Capitol Hill on Tuesday. (Eric Thayer/Reuters)

The White House and Republican House leaders came together Friday behind the plan now moving through Congress to overhaul the Affordable Care Act, including a provision criticized by conservatives pressing for a more aggressive attack on the law.

After President Trump met at the White House with key House committee chairmen, his chief spokesman said the president fully supports the bill’s timeline for phasing out the expansion of Medicaid under the ACA, which some on the right would like to accelerate. Earlier in the day, House leaders dismissed the idea of speeding up the phaseout, as they have done for several days.

“Right now, the date that’s in the bill is what the president supports,” White House press secretary Sean Spicer told reporters, adding, “It’s not a question of negotiation.”

Spicer’s comments indicated that Trump has taken the side of GOP leaders in their battle with House conservatives, who have been pressing for a more dramatic rollback of Obamacare for weeks and insist that the pending legislation cannot pass the House without significant changes.

The development also suggested that Trump had reversed himself after meeting with House leaders Friday; earlier in the week, the president told conservative lawmakers and leaders of outside conservative groups that he was open to significant further negotiations.

If so, Trump’s stance gives House Speaker Paul D. Ryan (R-Wis.), the measure’s top booster, new momentum at the end of a difficult week of conflict between conservative members of Congress and GOP leaders.

The chairman of the House Freedom Caucus, the hard-right faction that contains the plan’s most vocal Republican critics, insisted Friday that Trump’s position “has not changed,” citing “continued conversations” with White House budget director Mick Mulvaney.

“He’s willing to get the very best of any deal, and he knows that there is a real willingness to negotiate in good faith to get a better bill,” Rep. Mark Meadows (R-N.C.) said.

Both sides have been speaking to Trump, and each has hoped that he will help wear down the other, putting the president at the center of a fierce intraparty clash. Even now, the lack of clear guidance from Trump has left both sides jockeying to argue their case to him last.

Next week, the independent Congressional Budget Office is scheduled to release its estimates of the bill’s cost and impact on insurance coverage, threatening to upend the debate anew.

But Friday, the proxy battle concerned the ACA’s expansion of Medicaid, the federal health-care program for low-income Americans. The American Health Care Act, as the GOP proposal is named, would phase out the expansion by 2020, but conservatives want it to end next year.

House Majority Leader Kevin McCarthy (R-Calif.) said at a Friday news conference on Capitol Hill: “I think right now that would be very difficult to do.”

Before meeting with the committee chairs Friday, Trump congratulated them for advancing the legislation in marathon sessions this week and voiced optimism about the road ahead. “This is the time we’re going to get it done,” he said.

The GOP leaders said afterward that they were willing to listen to different perspectives but warned against stalling.

“We’ll continue to listen; we’ll continue to make improvements where we can,” said Rep. Kevin Brady (R-Tex.), chairman of the House Ways and Means Committee. “But there’s no question: This is the bill at the end of the day that will come to the president’s desk.”

“We are ready to go, and the worst thing we could do is hit the pause button and continue Obamacare and its broken policies,” said Rep. Greg Walden (R-Ore.), chairman of the Energy and Commerce Committee.

And in a Friday radio interview with conservative host Hugh Hewitt, Ryan warned that any deviation from the plan set in motion would be “momentum killing.”

Meadows said Ryan and other party leaders were being unreasonable: “To suggest that they’re willing to listen but that no substantial changes would be made sends a real clear message that ‘we appreciate your input, but we don’t appreciate your amendments.’ ”

Walden said Friday that changing the phaseout date would upset a carefully crafted bill that was negotiated with key parties off Capitol Hill.

“I’ve had discussions all along about different dates, different timelines with governors, with insurance commissioners, with leaders of each of these different groups,” Walden said. “What we want to make sure is that we don’t create a gap. . . . Our best effort is what you see before us.”

(Peter Stevenson/The Washington Post)

Friday’s White House meeting came the day after the House GOP proposal cleared the Ways and Means and the Energy and Commerce committees on party-line votes.

During a Thursday meeting with Trump and Mulvaney, Meadows and fellow Freedom Caucus member Rep. Jim Jordan (R-Ohio) expressed concerns about the House plan, including how it addresses the Medicaid expansion, said a person familiar with the gathering, speaking on the condition of anonymity to reveal details of a private conversation.

Trump expressed an openness, this person said, to moving up the Medicaid rollback but did not offer a “hard and fast” commitment.

Thirty-one states and the District of Columbia accepted the ACA’s Medicaid expansion, which obligated the federal government to cover 90 percent of the program’s expenses. Before the ACA, the federal government covered as little as 50 percent of expenses in many states.

The House GOP proposal would administer Medicaid by giving a fixed per capita amount of funding to states rather than covering a percentage of all health-care expenses incurred by enrollees.

The plan would also replace federal insurance subsidies in the ACA with age- and income-based tax credits.

Rep. Joe Barton (R-Tex.), the vice chairman of the Energy and Commerce Committee, offered an amendment at the panel’s meeting Thursday to speed up the phaseout of the Medicaid expansion. He ultimately withdrew it but said he expected to offer a similar amendment to the bill when it reaches the House floor.

“He didn’t say it would be impossible,” Barton said, responding to McCarthy’s suggestion that moving the date would be difficult. The White House, he said, is “studying it.”

Conservatives remained split Friday over which elements of the bill needed to change to win their votes. Some focused on rolling back Medicaid while others insisted that the legislation must eliminate requirements that insurers provide basic benefits, such as prenatal and maternity care.

(Sarah Parnass/The Washington Post)

Vice President Pence and Health and Human Services Secretary Tom Price met Friday with leaders of several conservative groups who have voiced opposition to the bill, in what one attendee described as a “serious” and “frank” discussion about the law. Many of the same leaders met Wednesday with Trump.

Many of the groups expressed a desire for more changes to the existing law than the Republican plan contains. According to two attendees, conservative activists pressed Pence and Price about the possibility of overriding the Senate parliamentarian, who limits what can be passed through the special budget rules governing the passage of the GOP proposal.

“Senator McConnell did say we were going to repeal Obamacare root and branch; he did not say we’re going to get my grandchild’s safety scissors and trim up Obamacare,” said Jenny Beth Martin, co-founder of the Tea Party Patriots, who participated in both meetings. “The bill as it is right now does not fully repeal Obamacare.”

According to Martin, Pence did not make any firm commitments in the meeting Friday but pointedly expressed the White House’s willingness to entertain the concerns of her group and others.

“The vice president said several times that it is a process, and we’re working through it and we’re open to changes,” Martin said.

Ashley Parker and Abby Phillip contributed to this report.