(Bastien Inzaurralde/The Washington Post)

President Trump threatened Thursday to try to knock off members of the House Freedom Caucus in next year’s elections if they don’t fall in line — an extraordinary move that laid bare an escalating civil war within a Republican Party struggling to enact an ambitious agenda.

In a series of tweets that began in the morning, the president warned that the powerful group of hard-line conservatives who helped block the party’s health-care bill last week would “hurt the entire Republican agenda if they don’t get on the team, & fast.”

The president vowed to “fight them” as well as Democrats in the 2018 midterm elections, a warning that his allies said was intended in the short term to make members of the Freedom Caucus think twice about crossing him again. But Trump’s pledge was met with defiance by many in the bloc, including some members who accused him of succumbing to the establishment in Washington that he had campaigned against.

Later in the day, Trump singled out three of the group’s members in another tweet, saying that if Reps. Mark Meadows (N.C.), Jim Jordan (Ohio) and Raúl R. Labrador (Idaho) got on board, “we would have both great healthcare and massive tax cuts & reform.”

Most of the roughly three dozen Freedom Caucus members were elected from safe Republican districts, and many of them faced no primary opposition. To make good on his threat, Trump would have to recruit GOP candidates to make the case that the Republican incumbent they face was unhelpful to an un­or­tho­dox, populist president.

Trump’s frustrations with the Freedom Caucus also reflect only part of his challenge in moving legislation, even in a Congress where his party controls both chambers. If Trump does too much to mollify members of the hard-line group, he risks alienating a similar number of more moderate Republicans in districts won or narrowly lost by last year’s Democratic presidential nominee, Hillary Clinton.

And on many pieces of Trump’s congressional agenda, he’ll need the support of at least some Democrats, particularly in the Senate, an uncertain prospect given the toxic partisan environment on the Hill.

House Speaker Paul D. Ryan (R-Wis.) told reporters a few hours after Trump’s first tweet on Thursday that he sympathized with him.

“I understand the president’s frustration,” Ryan said. “About 90 percent of our conference is for this bill to repeal and replace Obamacare and about 10 percent are not. And that’s not enough to pass a bill.”

Ryan said he had no immediate plans to bring the bill back to the House floor, saying it was “too big of an issue to not get right.”

Trump and his White House advisers have been particularly frustrated by the intransigence of several prominent Freedom Caucus members, led by Meadows.

In White House meetings, Trump lobbied them intensively, only to see the bill collapse last Friday after Meadows and some of his allies said they would not vote for it. The bill also faced strong opposition from a group of moderate Republicans who were concerned it went too far in cutting Medicaid and leaving millions more people without insurance.

(The Washington Post)

“This has been brewing for a while,” a White House official said of Trump’s decision to pressure and possibly target Freedom Caucus members.

“Our view is: There’s nothing as clarifying as the smell of Air Force One jet fuel. So if he needs to bring in the plane and do a rally, he’s going to think about doing that,” said the official, who requested anonymity because the official was not authorized to speak publicly.

The official added that Trump and White House aides are “sick and tired” of seeing Freedom Caucus members on television in recent days.

Trump’s threat comes as Republican leaders are bracing for a month of potential GOP infighting over spending priorities. Congress must pass a spending bill by April 28 to avert a government shutdown.

Beyond that, the same divide that derailed the health-care legislation could imperil the next marquee legislation that Trump wants to tackle: tax reform.

White House press secretary Sean Spicer told reporters Thursday that Trump remains committed to “a bold and robust agenda,” adding: “He’s going to get the votes from wherever he can.”

Since Friday’s debacle, Trump and his aides have increasingly talked up the possibility of working with Democrats on a reboot of the health-care bill and other priorities — but that prospect has also divided Republicans on Capitol Hill.

In in a CBS News interview that aired Thursday morning, Ryan said he does not want to see Trump have to work with Democrats on revamping the Affordable Care Act — drawing flak from some members of his own party, including Sen. Bob Corker (R-Tenn.), who said Trump’s bipartisan overtures should be encouraged.

“He’s irritated,” anti-tax advocate Grover Norquist said in explaining Trump’s decision to lash out at Freedom Caucus members. “During the health-care discussions, the Freedom Caucus would say they’d support him if they got one thing, then they’d want another thing. If you’re Trump, you wonder, ‘Why are these people meeting with me if they’re always going to be a ‘no’ vote?’”

If Trump gets involved in Republican primaries, Norquist said he thinks it’s possible he could “get some scalps.”

Though Trump’s national job approval numbers are historically low for a new president, he remains popular in many of the districts where Freedom Caucus members were elected. At the same time, most of those members won a larger percentage of the vote in their districts than Trump did.

On Capitol Hill, Trump’s tweet was met with a range of reactions: Some members said it could prove counterproductive while others praised him for using the power of his office in a way he hasn’t to this point.

Rep. Mark Sanford (R-S.C.), who has called for health-insurance reform to work its way through Congress more slowly, said that with Trump’s tweet on Thursday, the president was taking exactly the wrong approach.

“The idea of threatening your way to legislative success may not be the wisest of strategies,” Sanford said Thursday. “His message yesterday was that he wanted to work with Democrats; I guess the message today is, ‘We need to fight against Freedom Caucus members and Democrats.’ . . . It’s a case of shooting messengers who were, rightfully, pointing out problems in a bill that the American public has not shown a proclivity toward.”

Jordan, another Freedom Caucus member, said the break with Trump was based on real policy differences, not a lack of loyalty.

“The president can say what he wants and that’s fine. But we’re focused on the legislation,” Jordan said.

Some of the harshest responses to Trump came via Twitter, his preferred means of provocative communication. Those included a tweet from Rep. Justin Amash (R-Mich.), who said that Trump’s support of the health-care bill signaled he was now part of the Washington elite.

“It didn’t take long for the swamp to drain @realDonaldTrump,” said Amash, a member of the Freedom Caucus and one of Trump’s frequent GOP critics. “No shame, Mr. President. Almost everyone succumbs to the D.C. Establishment.”

Rep. Chris Collins (R-N.Y.), a Trump ally, said the president’s focus on the Freedom Caucus was well placed as the White House attempts to steady itself and rethink its congressional coalitions.

Collins, a member of the Tuesday Group, a group of moderate House Republicans, rejected the notion — put forth this week by members of both groups — that there could be an accommodation between them on the health-care bill.

“The Tuesday Group will never meet with the Freedom Caucus, with a capital N-E-V-E-R,” Collins said, spelling out the last word.

Some Republicans said they see potential for Trump forging a governing coalition that includes some Democrats.

“Trump is a New York-type bargainer who wants to get something done,” said Rep. Peter T. King (R-N.Y.). “That approach will give him a lot of room to maneuver on taxes and infrastructure. Once you break the barrier that every bill has to have total Republican support, you can be more creative.”

Michael Steel, who was a senior aide to former House speaker John A. Boehner (R-Ohio), said there is potential in some districts for Trump to dislodge Freedom Caucus members.

“If the president chooses to support primary challengers to House members who’ve been unhelpful, it wouldn’t necessarily be an ideological challenge,” Steel said. “It would be based on loyalty to the president, or lack thereof.”

But Steel added: “You don’t necessarily have to wait for 2018 for this to have an effect.”

There is precedent for Republican leaders taking aim at Freedom Caucus members. A spate of 2015 ads purchased by the American Action Network, a nonprofit issue advocacy group with ties to House GOP leaders, targeted Jordan and two other hard-liners for opposing a Department of Homeland Security funding bill.

Those ads infuriated members of the caucus, then only months old, and spawned a confrontational relationship that culminated in Boehner’s resignation six months later.

One open question is whether the National Republican Congressional Committee, the GOP’s House campaign arm, would intervene on behalf of incumbents targeted by Trump.

Rep. Steve Stivers (R-Ohio), the NRCC’s chairman, chuckled Thursday after a reporter read him Trump’s tweet.

“I want to be very clear: We have a policy of helping out incumbents that pay their dues,” Stivers said, referring to the hundreds of thousands of dollars GOP lawmakers are expected to raise for the committee each election cycle. “As long as they pay their dues, we’re gonna be there for them. . . If I was them, I’d take a look and see how I’m doing on my dues.”

Philip Rucker, David Weigel, Sean Sullivan and Scott Clement contributed to this report.