A group of nine moderate House Democrats told Speaker Nancy Pelosi that they will not vote for a $3.5 trillion budget blueprint until a Senate-approved infrastructure bill clears the chamber, a posture that underscored significant divisions within the party that could undermine President Biden’s economic agenda.

The demand on Friday threatened to leave the House in a new political deadlock, roughly two weeks before lawmakers are set to return to the Capitol to begin debate. Liberal Democrats have demanded the opposite timeline, leaving Pelosi (D-Calif.) in a tough bind given that Democrats have a narrow majority and few votes to spare.

The budget resolution, which Senate Democrats adopted Wednesday over GOP objections, opens the door to significant overhauls in health care, education, immigration and the tax code. The infrastructure package, which cleared the chamber in a bipartisan 69-to-30 vote, sets aside $1.2 trillion to improve the country’s roads, bridges, pipelines, ports and Internet connections.

The Fix’s Amber Phillips analyzes the significance of two Senate infrastructure votes this week and how soon the measures could be signed into law. (JM Rieger/The Washington Post)

Biden has sought passage of the two bills in tandem, particularly as he tries to strike a balance between both wings of his party. On Friday, the White House steered clear of engaging the Democratic dispute directly: Without commenting on the order of operations, press secretary Jen Psaki said in a statement the administration remains “confident” the House will adopt both economic packages after successful votes in the Senate this week.

“America needs to make long overdue investments in highways and bridges; to remove lead drinking water pipes that damage the health of our children; and to connect everyone to the internet,” Psaki added. “America also needs to help families with their living expenses: bringing down the costs of child care and health care; extending the tax cut for 40 million families; and promoting clean, affordable energy. Both are essential, and we are working closely with Speaker Pelosi and the leadership to get both to the president’s desk.”

Still, the proposals have created a rift among some Democrats over which, exactly, should come first.

Earlier this spring, the 96-member Congressional Progressive Caucus issued the first ultimatum, telling Democratic leadership that its bloc would not vote to advance an infrastructure bill without first adopting the budget. The caucus has said the $1.2 trillion package falls far short of the spending they see as necessary to tackle issues including climate change, so they have insisted the House and Senate must begin its work by acting on the budget.

“Our Caucus is clear: the bipartisan bill will only be passed if a package of social, human, and climate infrastructure — reflecting long-standing Democratic priorities — is passed simultaneously through budget reconciliation,” Rep. Pramila Jayapal (D-Wash.), the chair of the group, said in a statement on the day the caucus reaffirmed its threat in a new letter to the speaker.

Pelosi largely has acceded to the demands of the more liberal Democrats in the chamber, telling the fuller Democratic caucus on a call this week that the bipartisan infrastructure deal, while welcome, “ain’t the whole vision,” according to a person familiar with the conversation who spoke on the condition of anonymity to describe the private gathering.

But Pelosi’s approach has not been sitting well with moderates, who have harbored concerns for months about the size and scope of the $3.5 trillion budget — and the means by which Democrats may try to pay for it using tax increases. That prompted the moderate bloc to issue its own letter with an ultimatum Thursday, saying infrastructure must come first.

“Some have suggested that we hold off on considering the Senate infrastructure bill for months — until the [budget] reconciliation process is completed. We disagree,” said the letter from moderates, dated Thursday. “With the livelihoods of hardworking American families at stake, we simply can’t afford months of unnecessary delays and risk squandering this once-in-a-century, bipartisan infrastructure package. It’s time to get shovels in the ground and people to work.”

The letter, first reported by Punchbowl News, was signed by Reps. Carolyn Bourdeaux (D-Ga.), Ed Case (D-Hawaii), Jim Costa (D-Calif.), Henry Cuellar (D-Tex.), Jared Golden (D-Maine), Vicente Gonzalez (D-Tex.), Josh Gottheimer (D-N.J.), Kurt Schrader (D-Ore.) and Filemon Vela (D-Tex.).

By Friday morning, Pelosi had not signaled any change in plans — and some party aides appeared to cast doubt on any chance that she might. One senior Democrat, speaking on the condition of anonymity to describe the party’s thinking, said there are dozens of lawmakers who would vote against the bipartisan infrastructure deal if the speaker moves to that proposal first. Privately, though, moderates grouse that there may be votes to gain among Republicans, given the fact that 19 GOP lawmakers joined with Democrats in the Senate in passing the infrastructure bill this week.

“The country is clamoring for infrastructure investment and commonsense, bipartisan solutions,” the House moderates say in their letter. “This legislation does both, and will help us compete with China and others in the global economy. There is a reason why the bipartisan bill has the strong support of groups ranging from the AFL-CIO to the U.S. Chamber of Commerce.”

Seung Min Kim contributed to this report.