House Democrats envisioned their three-day policy retreat as a celebration of 100 days in power and a unity-building exercise ahead of upcoming major political and policy fights.

Instead, after a show of strength from the party’s left flank, leaders are confronted with fresh questions about their caucus’s cohesion and whether they can muster a united front against President Trump and Republicans for approaching showdowns on immigration, health care and spending — not to mention a 2020 campaign looming larger by the day.

On Tuesday, Democratic leaders suddenly postponed a vote on federal spending levels for 2020 — a vote meant to serve as a strong opening bid for coming fiscal negotiations — after liberal lawmakers balked at a compromise with Democratic moderates that left a disparity between funding for defense and domestic programs.

Addressing reporters at the start of the retreat Wednesday, Democratic leaders highlighted the historic diversity of the freshman class and played down any notion of persistent division.

“Our diversity is our strength, our unity is our power, and that unity is how we’re building consensus around issues here,” Speaker Nancy Pelosi (D-Calif.) said, deploying one of her favorite aphorisms.

House Majority Leader Steny H. Hoyer (D-Md.) went a step further, arguing that Democrats actually notched a triumph, not a setback, because a provision embedded in a procedural vote would allow Democrats to draft the spending bills later this year.

“We’ve had 100 days of success, and yesterday was no exception,” Hoyer said, before suggesting that leaders would have put up a bigger fight if the stakes were higher: “Very frankly, we wouldn’t have lost any vote this week if we wanted to win.”

The revolt Tuesday came after several occasions over the past three months where left-wing lawmakers agreed to set aside concerns in the interest of party comity. That ended Tuesday, and liberal leaders warned in the aftermath that their votes were no longer to be taken for granted.

“Hopefully there’s a good lesson to be learned as we move on to the rest of the session — that when 40 percent of the caucus has a position, it may be a good position to listen to,” said Rep. Mark Pocan (D-Wis.), co-chair of the Congressional Progressive Caucus. “We were able to show a little bit of leverage.”

The show of strength echoed the ideological infighting that plagued Republicans during their eight-year majority that ended with the Democrats’ midterm triumph in November. Hard-right lawmakers in the House Freedom Caucus stuck together to complicate, and sometimes foil, GOP leaders’ plans to pass spending, health-care, agriculture and other bills they found too accommodating to Democrats.

Asked whether Tuesday’s budget implosion reminded him of the GOP’s sparring, House Budget Committee Chairman John Yarmuth (D-Ky.) laughed and said, “It’s like looking in the mirror.”

Despite encouragement from outside liberal groups, left-leaning Democrats have yet to officially form a smaller, more hard-line cohesive bloc willing to hold firm against pressure from colleagues. But Tuesday’s rebellion made clear that a couple dozen members of the nearly-100-member-strong Progressive Caucus are tired of being seen as political doormats and are willing to sink legislation to make a point.

“Hopefully the signal that it sends is, ‘Please come and talk to us; we have to be a part of the process,’ ” said co-chair Pramila Jayapal (D-Wash.), who has firmly resisted calls for her caucus to form the equivalent of the Freedom Caucus.

She added: “We’ve tried to do that in the most respectful way possible — it’s not our intention to blow things up — but we do need to be consulted.”

Ideological infighting is certainly not on the official agenda for the retreat, held at the Lans­downe Resort and Spa in Leesburg, Va. Instead, the sessions focus on such topics as youth voter engagement, racial justice and political messaging, as well as various policy issues.

One session is titled “Staying on Message During the Trump Presidency,” an issue that has flummoxed lawmakers trying to tout legislative achievements. Others focus on health care, infrastructure and labor policies.

Members are set to hear from a wide variety of speakers from politics, business, entertainment and academia — though many of the party’s most prominent names are not speaking because they are running for president.

Former Massachusetts governor Deval Patrick, who opted against a 2020 run, is scheduled to deliver Wednesday night’s keynote address, and tech journalist Kara Swisher will give a keynote Thursday ahead of an appearance by Federal Reserve Chair Jerome H. Powell.

In one sign that complete unity will be elusive, dozens of Democrats are expected to be absent from the gathering — choosing to return to their districts to campaign and spend time with their families rather than with their colleagues ahead of a two-week congressional recess. Many are moderates representing battleground districts, and many are freshmen.

“I have a very competitive district, and I have a primary, and I have five town halls in the next week,” said Rep. Tom O’Halleran (D-Ariz.), a second-term moderate. “People expect me to be out there.”

By all accounts, Democrats have had a busy start to their majority. The first quarter was spent in the longest-ever federal government shutdown, one that ended in victory for Democrats who held firm against Trump’s demands for border wall money. Trump subsequently declared a national emergency to circumvent Congress; the House filed suit last week to prevent the move.

Since then, Democrats have passed other key bills, including a wide-ranging overhaul of ethics and elections laws, an expansion of firearm background checks, and a renewal of the Violence Against Women Act. They have also passed resolutions condemning Trump administration policies, including its support for the Saudi war in Yemen, its ban on transgender troops and its backing of a lawsuit seeking to overturn the Affordable Care Act. 

But Democrats face the reality of limits on their power in divided government, as Republicans control the Senate and Trump the White House.

“You don’t accomplish as much as we’ve accomplished in such a short period of time without working as a team,” said Rep. David N. Cicilline (D-R.I.), chairman of the Democratic Policy and Communications Committee. “That does not mean everybody on the team has the same exact view on every issue, but we are very united.”

But in other areas, their legislative record remains incomplete — including on several of their signature campaign issues such as health care and infrastructure. Retreat sessions on those issues — as well as trade policy, fiscal responsibility and a potential minimum wage increase — could produce the same divisions among Democrats that were on display in the budget dispute this week.

Leaders, for example, hope to spend little time discussing Medicare-for-all, an idea backed by liberals but that Pelosi has shelved amid concerns about cost and viability. But on Wednesday, 2020 hopeful Sen. Bernie Sanders (I-Vt.) rolled out his own version of the single-payer system, a reminder of the split between House leaders and those running for the presidency that is sure to surface in the health discussion at the retreat.

It’s not just liberals who have dug in, creating tensions in the caucus. At least a dozen moderates were prepared to oppose the budget caps proposal on grounds of fiscal responsibility. 

These members have also pushed back on liberals as they try to move the caucus left, expressing concerns about losing their majority by putting swing-district Democrats in political jeopardy.

“Republicans added trillions of dollars to the debt and deficit,” said Rep. Kurt Schrader (D-Ore.), a co-chair of the moderate Blue Dog Coalition. “We’re . . . trying to be responsible, for goodness sakes.”

Republicans, meanwhile, deemed the Democratic majority a “disappointment,” criticizing them for pulling their budget legislation, “harassing” Trump with investigations and taking symbolic votes on several issues, including health care. But more than anything, they accused Democratic leaders of acquiescing to their party’s most liberal voices.

“Our Democratic colleagues need to decide: Are they the party of John F. Kennedy? Or are they the party of Alexandria Ocasio-Cortez and Bernie Sanders?” said Rep. Liz Cheney (R-Wyo.), the GOP Conference chairwoman. “They cannot be both.”

Liberal leaders couched their opposition to the budget legislation as a warning shot — one fired on an issue that, for the time being, has no practical effect on governance. But they are warning party leaders that future missteps could have a more significant impact.

“Fortunately for them, this isn’t that big of an issue for the American people,” Pocan said. “It’s kind of an inside-the-Beltway thing. But hopefully the lesson learned is, include everybody — including a Progressive Caucus that has been very outspoken in what we were trying to do — and make sure we’re part of it.”