WASHINGTON (NewsNation Now) — The House on Tuesday voted to pass a $3.5 trillion budget blueprint that would expand spending on social programs and advance a $1 trillion infrastructure bill already passed by the Senate.

The afternoon came after a turbulent 24 hours that brought the House to a standstill. Tensions flared as a band of moderate lawmakers threatened to withhold their votes for the $3.5 trillion plan. They were demanding the House first approve a nearly $1 trillion bipartisan package of other public works projects that’s already passed the Senate.

In brokering the compromise, House Speaker Nancy Pelosi committed to voting on the bipartisan package no later than Sept. 27. That’s an attempt to assure lawmakers it won’t be left on the sidelines, but it is in line with Pelosi’s insistence that the two bills move together as a more complete collection of Biden’s priorities. Pelosi has set a goal of passing both by Oct. 1.

Pelosi told her colleagues before the vote that the legislation would lead to a federal investment on par with the New Deal and the Great Society.

She brushed aside the delays. “That’s just part of the legislative process,” she said, according to an aide granted anonymity to discuss a closed-door caucus meeting.

“Not only are we building the physical infrastructure of America, we are building the human infrastructure of America,” Pelosi said on the House floor.

What was supposed to be a quick session as lawmakers returned to work for a few days in August devolved into a display of the party differences that threaten to upend Biden’s ambitious rebuilding agenda.

With Republicans fully opposed to the president’s big plans, the Democratic leaders have just a few votes to spare. That gives any band of lawmakers leverage that can be used to make or break a deal, as they are poised to do in the weeks to come as moderates and progressives draft and vote on the broader $3.5 trillion package.

“I think it’s important to those of us who are moderate Democrats to make sure that our voices are heard,” said Rep. Jim Costa, D-Calif., one of the negotiators.

Challenging their party’s most powerful leaders, nine moderate Democrats signed onto a letter late last week raising their objections to pushing ahead with Biden’s broader infrastructure proposal without first considering the smaller public works plan that has already passed the Senate.

Their ranks grew as other moderates raised similar concerns.

Progressives were outraged at the moderates, blaming them for potentially jamming Biden’s agenda, which is stocked with hard-fought party goals like child care, paid family leave and a Medicare expansion.

Outside groups, including Justice Democrats, started running campaign ads and members of Our Revolution, the organization aligned with Bernie Sanders, protested Tuesday outside the New Jersey office of Rep. Josh Gottheimer, a leader of the moderate effort.

“This is a ‘which side are you on‘ moment,'” Our Revolution executive director Joseph Geevarghese told The Associated Press. Geevarghese promised to “organize like never before to hold Democrats accountable and get this bill over the finish line.”

The budget measure is at the heart of Biden’s “Build Back Better” vision for helping families and combating climate change and is progressives’ top priority, all of it largely financed with tax increases on the rich and big business.

The House committees are already fast at work drafting legislation to fill in the details of the $3.5 trillion package for consideration later this fall.

Progressives signaled early on they wanted the Biden budget priorities first before they agree to the smaller Senate package, worried it would be an insufficient down-payment on his goals.

But the moderates want the opposite, insisting Congress quickly send the smaller, bipartisan infrastructure measure they helped shape with the senators to Biden so he can sign it before the political winds shift.

While the moderates insist they also want to support Biden’s broader package, progressives are skeptical. Senate centrists Sen. Joe Manchin, D-W.Va., and Sen. Kyrsten Sinema, D-Ariz., have said they cannot support a $3.5 trillion package.

In fact, the moderates were also trying to win assurances from Pelosi that whatever version of the broader bill they draft in the House will be the same in the Senate — setting up another showdown between the party’s competing flanks and their vision for the rebuilding priorities.

So far, the White House has backed Pelosi as she has led her party in a tightly scripted strategy.

White House press secretary Jen Psaki on Monday underscored Biden’s support for Pelosi’s plans. Psaki deemed it a “healthy debate” within the party.

Republicans plan to reject the the $3.5 trillion effort as big government spending, and GOP support for the slimmer $1 trillion bipartisan measure is now uncertain.

The conservative House Freedom Caucus said it opposes both the Biden budget and the bipartisan bill.

Republicans blasted Democrats for pursuing their priorities at a time when they said all focus should be on Afghanistan, as thousands of people including Americans are trying to flee the country as the U.S. withdraws its forces.

“We should be doing nothing else on this floor until every single American is home,” said Rep. Kevin McCarthy, the House minority leader.

Inserting his own wedge into the politics of the situation, Senate Republican leader Mitch McConnell said Tuesday on Fox News that he was rooting for the House moderates.

“I wish the moderates in the House success,” McConnell said. “I’m pulling for them.”