WASHINGTON – With a roughly $1.2 trillion bill to improve the nation’s infrastructure now behind them, Democrats must prepare to turn to their next, perhaps tougher task: Shepherding the rest of President Biden’s economic agenda through Congress.

The successful vote in the House late Friday marked only the first of two spending initiatives that Biden has called on Congress to adopt for months. Still another roughly $2 trillion in new tax and spending investments are awaiting action in the House and Senate, where party lawmakers harbor grand ambitions to overhaul the nation’s health care, education, climate, immigration and tax laws.

Beginning in the spring, many Democrats had hoped to move these two bills in tandem, a strategy meant to satisfy liberals and moderates who were warring with each other over the size and scope of their spending priorities. But the House this week essentially opted to divorce them, adopting an infrastructure bill that had been stalled since August while voting to open debate on the remainder of their plans.

That tees up for Congress an eleventh-hour sprint in the waning moments of the year through treacherous political terrain. The $2 trillion tax-and-spending proposal is still unsettled policy in the eyes of moderates, including Sen. Joe Manchin, D-W.Va., who long has sought to whittle down its price tag. And the debate is set to arrive just as Congress is preparing to take on a host of additional challenges, including a renewed need to fund the government in December, that could distract Democrats in the end.

For all the hurdles they face, however, Democrats this week sounded an upbeat note – emboldened anew after achieving a fresh political victory.

“Let me be clear: We will pass this in the House. And we will pass it in the Senate,” Biden said during a speech Saturday heralding the passage of the infrastructure bill.

The $2 trillion measure – called the Build Back Better Act, which bears the name of the president’s 2020 campaign slogan – aims to expand the footprint of government to deliver more robust services to American workers and families, especially those in greatest need.

Democrats aspire as part of the package to expand Medicare benefits to cover hearing aids and lower the price of insulin and other prescription drugs for seniors. They also hope to institute free, universal prekindergarten and provide billions of dollars to boost child care. Party lawmakers have included one of the largest investments ever to combat climate change, a new effort to reform the country’s immigration system and a slew of expanded tax benefits to help families with children. And they have proposed to fund the measure through new taxes on millionaires and profitable corporations.

The focus on what some call “social” spending differs considerably from the infrastructure bill, which trains its investments on improving the country’s roads, bridges, pipes, ports and internet connections. But both plans grew out of the same series of policy blueprints that Biden put forward this spring, as he pledged to revitalize the U.S. economy in the aftermath of the coronavirus pandemic.

The infrastructure bill is soon set to become law. The $2 trillion package, meanwhile, has yet to clear either chamber and has drawn considerable Republican opposition. Instead, Democrats in Congress are preparing to return to the package later in November, embarking anew in a debate that has divided the party considerably since the spring.

The first hurdle is the House, where Democrats are eyeing the week of Nov. 15 to consider the $2 trillion proposal. The time frame stems from an agreement between liberals and moderates that helped put an end to months of fighting and paved the way for the infrastructure bill to clear the House on Friday.

For months, left-leaning lawmakers with the Congressional Progressive Caucus had held up the public-works bill as leverage in talks with centrists over their broader spending ambitions. In doing so, they insisted both proposals had to move in tandem to win their support. But they ultimately agreed to ease their blockade in a late-night Friday compromise with a group of moderates that had been in revolt. Liberals said they would back infrastructure, assuaging centrists, who in turn pledged they would support the Build Back Better Act, provided they can see an official analysis of its fiscal impacts to determine if it is deficit neutral. (The bill’s top backers say it is funded in full.)

“We commit to voting for the Build Back Better Act, in its current form other than technical changes, as expeditiously as we receive fiscal information from the Congressional Budget Office,” said five moderates, including Rep. Stephanie Murphy, D-Fla., a leader of the Blue Dog Coalition, and Rep. Josh Gottheimer, D-N.J., who helped broker the pact. They also promised to work “to resolve any discrepancies” if the budgetary analysis is unfavorable.

Joining moderates on the steps of the Capitol to announce the truce, Rep. Pramila Jayapal, D-Wash., the head of the Congressional Progressive Caucus, stressed the two factions are “going to trust each other because the Democratic Party is together on this.”

“We’ve always said we need to get both bills done,” Jayapal told reporters. “And tonight we have an agreement that will get both bills done.”

The agreement is critical in the narrowly divided House: House Speaker Nancy Pelosi, D-Calif., can only afford to lose three votes in the narrowly divided chamber, where Republicans vehemently oppose the measure and are unwilling to aid in the same way they did with the infrastructure deal. If liberals and moderates are not in lockstep, the entire $2 trillion endeavor would be doomed.

Speaking to reporters Friday, Pelosi expressed a measure of confidence that they could ultimately finalize the bill in the House in the coming weeks. “As we do, then, we’ll have a Thanksgiving gift for the American people,” she said.

The package then heads to the Senate, where the battle is likely only to intensify. There, centrists including Manchin and another moderate holdout, Sen. Kyrsten Sinema, D-Ariz., for months have angled to whittle down Democrats’ spending ambitions. Their campaign already has forced the party to scale back the bill from its original $3.5 trillion size, a process that forced them to jettison some of their original policy priorities – including a fulsome expansion of Medicare and a plan to provide community college for all Americans.

And the cuts may not be finished.

Manchin, for example, has insisted for months the package should be capped at $1.5 trillion – though at one point he appeared open to the $1.75 trillion ceiling that Biden put forward as a potential compromise in October. Manchin never did endorse that framework anyway, rankling liberal Democrats, who long have felt they have slashed their signature spending initiative too dramatically.

In the days before the House finalized its bill – and held a key procedural vote late Friday to open debate – Pelosi and her top aides went as far as to add funds and programs to the measure that could draw Manchin’s ire. That included a plan to offer four weeks of paid family and medical leave to millions of Americans, a widely supported program that the West Virginia senator previously has opposed as part of the package.

Even Biden on Saturday appeared to acknowledge the potential changes on the horizon as Democrats advance it through the Senate. Asked about the future of the paid-leave proposal, the president replied: “Time will tell.”

Manchin is not the sole obstacle in the chamber, where concerns linger among a wider community of lawmakers. Even Sen. Bernie Sanders, I-Vt., the architect of the original $3.5 trillion spending blueprint, has taken issue with the House-drafted bill for the way it handles state and local taxes – restoring a deduction, he has said, that amounts to an “absurd and hypocritical” tax break for higher-income earners.

But an even tougher test may not come from any senator at all. To pass their package in the narrowly divided chamber, where Democrats have only a tiebreaking advantage, the party has opted to rely on a process known as reconciliation. It allows them to avoid a GOP filibuster, but it carries strict rules that limit the measure to proposals with clear budgetary effects.

To stay within the confines of reconciliation, Democrats have to craft their proposal carefully and survive scrutiny from the chamber’s parliamentarian. Otherwise, entire portions of the bill could be struck – a prospect that looms especially large over the party’s plans to try to address immigration in the so-called Build Back Better Act. The newly revised House bill would allow the government to “parole” undocumented immigrants by giving them five-year work permits that shield them from deportation. The Senate’s rulekeeper previously has advised Democrats against including some immigration policies in the package.

The Senate process is long and arduous, allowing lawmakers in the course of debate to offer unlimited amendments in what typically becomes a marathon, overnight process known as a vote-a-rama. And any changes in the chamber could force the Senate to send the bill back to the House.

In working through those issues, Senate Majority Leader Chuck Schumer, D-N.Y., has joined Pelosi in setting out an ambitious timeline, stressing last week that chamber Democrats hope to complete work on the bill before Thanksgiving. The call for haste has hardly sat well with Manchin, however, who repeatedly in recent days has urged his party to slow down.

“We have to be very careful with a timeline – don’t even set a timeline until we thoroughly, thoroughly vet this entire bill,” he said Wednesday.