Congressional Democrats on Wednesday began the grueling political task of slimming down their signature initiative to overhaul the nation’s health-care, education, climate and tax laws, as President Biden hit the road to sell his broader economic vision to voters.

The work began in Washington, where party lawmakers toiled anew to reduce the size and scope of a spending package once valued at about $3.5 trillion. In a sign of the compromises Democrats must now make to defuse a conflict within their own ranks, they huddled with top administration officials to rethink the tax increases on the wealthy and corporations that they initially hoped would pay for the new spending.

Biden, meanwhile, traveled to Scranton, Pa., in what marked the first in a series of trips to sell his sweeping economic agenda to the electorate. Taking the stage in the city where he was born, the president called for new spending to aid workers and parents as well as additional money for the nation’s roads, bridges, pipes and other aging infrastructure — promising to act after the nation “stopped investing in ourselves.”

The direct appeal marked a renewed attempt by Biden to right a debate that at times has pit his own party against itself. For months, the war between ambitious liberals and spending-weary moderates has resulted in a stalemate on Capitol Hill, precluding Democrats from delivering on the very promises that many in the party ran on during the 2020 election.

Even before arriving in Scranton, the president and his top aides had redoubled their efforts to broker a truce. Over the past two days, they presented to key party lawmakers a revised policy outline that could total as much as $2 trillion, with most of the spending financed through tax increases that chiefly target the ultrawealthy.

The twin developments offered Democrats a potential way forward — but threatened to test the party’s appetite for political compromise. The still-fluid price tag amounted to far less than the $3.5 trillion that some Democrats initially envisioned, reflecting the cuts they must make to satisfy two centrist holdouts, Sens. Joe Manchin III (D-W.Va.) and Kyrsten Sinema (D-Ariz.). And the financing proposal departed significantly from Democrats’ original plan to repeal the tax cuts enacted under former president Donald Trump, representing another concession to Sinema.

Facing potentially uncomfortable trade-offs, the political dynamic left some Democrats newly uneasy, nearly a year after securing their narrow yet potent majorities in Washington on a pledge to pursue a robust economic agenda. But Democratic leaders responded by stressing the urgent need to bring the debate to an end, a message Biden himself echoed in his speech Wednesday.

“These bills are not about left versus right, or about moderate versus progressive,” Biden said. “These bills are about competitiveness versus complacency, about expanding opportunity, not having opportunity denied.”

The flurry of activity reflected Democrats’ reinvigorated attempts to secure a broader spending deal before the end of the week. Party lawmakers have expressed confidence in recent days that such an achievement is within their grasp, allowing them to advance the massive spending package along with a separate yet related $1.2 trillion measure to improve the nation’s infrastructure, which passed the Senate earlier this year.

“I think we’ll get a deal,” Biden said as he prepared to board Air Force One en route to Pennsylvania.

Democrats long have harbored ambitions about their still-forming “Build Back Better” initiative, whose name comes from Biden’s 2020 campaign slogan. Lawmakers aim to expand Medicare and other health-care programs, provide universal prekindergarten while expanding other education programs, set aside new sums to combat climate change and offer fresh aid for families that are struggling financially.

But achieving those goals — all the while setting a price tag that Democrats broadly can support — have proved to be among the most vexing policy challenges facing Biden and his congressional allies. It has divided the caucus and complicated the task to adopt the bill, which Democrats can shepherd through the narrowly divided Senate only if they remain in lockstep.

With his governing agenda on the line, Biden on Wednesday hit the road, beginning a new swing of trips to sell his economic initiatives that are set next to take him to Baltimore and Newark. Appearing in Scranton, the president said the sum of Democrats’ efforts would catalyze a “fundamental shift in how our economy works.”

As Biden spoke, his top aides continued laboring alongside Democratic lawmakers on the finer details of that economic package. The White House this week offered an early blueprint that could see Democrats spend $1.75 trillion to $1.9 trillion on their agenda, a far cry from what some liberal lawmakers including Sen. Bernie Sanders (I-Vt.) initially sought.

The still-forming deal appears to open the door for Democrats to secure many of their long-sought spending programs. But these and other initiatives still stand to see significant cuts that could limit their duration or the number of Americans they cover, while others still have not been worked out in full — setting the stage for a frenetic next few days of further negotiations.

“We agree that we don’t help anybody if we don’t get a bill across the finish line,” said Rep. Suzan DelBene (D-Wash.), the leader of the center-left New Democrat Coalition, who has met with Biden multiple times in recent weeks.

Democrats appear to be on the verge of securing billions of dollars in funding to combat climate change, for example, including a potential end to tax subsidies for fossil fuel companies. But they also are likely to jettison a key program to incentivize clean energy production at the behest of Manchin, who represents a coal-heavy state. Its omission angered some Democrats, who took to the steps of the Capitol on Wednesday to continue to stump for aggressive spending in response to global warming.

“It would be a dereliction of duty to build the infrastructure of America without doing so in a green way that protects the planet,” House Speaker Nancy Pelosi (D-Calif.) said at a news conference, hours after she told lawmakers she felt a deal this week is still “very possible.”

Under the blueprint sketched out by the White House, Democrats also may be able to set aside new funding to expand Medicare to provide hearing, vision and dental benefits. But new concerns arose Wednesday that it would not be enough to deliver the robust, immediate coverage that Sanders and his allies initially had proposed.

Still another plan to provide universal prekindergarten remains intact, but Democrats could end up shelving a related effort to provide two years of community college to Americans tuition-free. And an effort to extend expanded child tax credits might have to be scaled back, after White House aides presented a plan that would authorize it only for the next year rather than permanently.

Many Democrats across the political spectrum reacted poorly to that idea Wednesday, signaling a tough slog still to come. An incensed Rep. Rosa L. DeLauro (D-Conn.) said she had already made clear to Pelosi as well as Biden’s top aides that they must secure a longer extension of the child tax credit, which Democrats expanded — and provided in the form of monthly payments — earlier this year as part of their coronavirus aid package.

“I said very clearly, I think it’s a mistake and I think it’s a missed opportunity for the country,” DeLauro said about the tax credit being extended only for a year.

Many of the prospective changes illustrated the pervasive political influence of Manchin and Sinema, without whom Democrats cannot proceed. Yet neither of the centrist lawmakers revealed their thinking Wednesday, even as Democrats continued to whittle down some of their spending priorities in an attempt to achieve their support.

Sinema’s office declined to comment, continuing a prolonged period of public silence from the Arizona senator. Manchin merely acknowledged to reporters that talks are underway.

Sanders, meanwhile, largely did not address any of the potential cuts after he had helped assemble Democrats’ original $3.5 trillion blueprint. Instead he told reporters, “What’s acceptable to me is to do what the American people want.”

Some of the potential concessions cut at core promises Democrats made during the 2020 election, including a pledge from Biden and top party lawmakers to raise tax rates on corporations and wealthy Americans to pay for their new spending. The president repeatedly called for the increases — which would reverse the cuts imposed under Trump in 2017 — arguing that the people benefiting most from the U.S. economy are not paying their fair share.

Instead, White House officials told Democrats during a private video meeting Wednesday that they now believe they can adopt only a more scaled-back plan that targets the ultrawealthy, including tax increases on billionaires and companies when they repurchase their own stock. The change in course reflected Sinema’s sustained opposition to significant new tax increases, even as she and other centrists insist that the new tax-and-spending measure must be financed in full so that it does not add any new government debt.

Among the officials on the White House call were White House National Economic Council Director Brian Deese; Treasury Secretary Janet L. Yellen; House Ways and Means Committee Chairman Richard E. Neal (D-Mass.); and Senate Finance Committee Chairman Ron Wyden (D-Ore.), according to two people familiar with the matter, who spoke on the condition of anonymity to describe the closed-door discussion.

Biden, however, still called for significant changes to the tax code during his speech Wednesday — stressing that the system that allows the wealthy to pay less “needs to change.” Some Democrats also pledged Wednesday that they are not yet ready to give up on their long-sought plans.

“I stressed the importance of putting an end to America’s two tax codes, and finally showing working people in this country that the wealthiest Americans are going to pay taxes just like they do,” Wyden said in a statement after the meeting, confirming his participation.

With so much still to resolve, Democratic leaders in the House and Senate still sought to hold the line — stressing in a flurry of private meetings and public interviews that they must remain united.

“They understand that you’ve got to get everybody in the tent, because we have very close margin,” House Majority Leader Steny H. Hoyer (D-Md.) said earlier Wednesday. “I think they’ll accommodate that.”