WASHINGTON— With President Joe Biden's government overhaul at stake, Democrats charged into trouble Thursday as a promised vote on the first piece, a slimmer $1 trillion public works bill, faltered amid stalled talks on his more ambitious package.

House Speaker Nancy Pelosi assembled her leadership team for an early morning meeting ahead of what would be a high-profile setback if voting on the public works bill fails or has to be scrapped.

Democrats are deeply at odds with trust torn, as progressive lawmakers threaten to withhold votes on the roads-and-bridges infrastructure bill they view as insufficient unless it is paired with Biden's broader vision. In the narrowly controlled House, Pelosi has no votes to spare.

All this on a day that should be a win for Biden and his party with Congress poised to quickly usher through legislation to keep government running past Thursday's fiscal yearend deadline and avert a federal shutdown that had been threatened by Republican blockades. 

"One hour at a time," Pelosi said at the Capitol. 

The risks are clear, but so is the potential reward as Biden and his party reach for a giant legislative accomplishment — promising a vast rewrite of the nation's balance sheet with an ever-slim majority in Congress. His idea is to essentially raise taxes on corporations and the wealthy and use that money to expand government health care, education and other programs — an impact that would be felt in countless American lives.

The public works bill is one piece of that broader vision, a $1 trillion investment in routine transportation, broadband, water systems and other projects bolstered with extra funding. It has won broad, bipartisan support in the Senate but has now become snared by the broader debate.

Attention is focused on Sens. Joe Manchin of West Virginia and Kyrsten Sinema of Arizona, centrist Democrats who helped steer that bipartisan bill to passage, but a concern that the overall size of Biden's plan. They view it as too big, but have infuriated colleagues by not making any counter-proposals public.

Tensions spiked late Wednesday when Manchin sent out a fiery statement, decrying the broad spending as "fiscal insanity" and warning it would not get his vote without adjustments. "I cannot — and will not — support trillions in spending or an all-or-nothing approach," he said.

Manchin's refusal to bring negotiations with Biden to a close enraged progressive lawmakers and almost ensured they would tank the bipartisan public works bill if there was no end in sight to the White House talks with the centrist senators.

Democrats' campaign promises on the line, the chairwoman of the Congressional Progressive Caucus, Rep. Pramila Jayapal of Washington state said after Manchin's statement: "We probably have even more people willing to vote no on the bipartisan bill."

In a deepening party split, centrists warned off canceling Thursday's vote as a "breach of trust that would slow the momentum in moving forward in delivering the Biden agenda," said Rep. Stephanie Murphy, D-Fla., a leader of the centrist Blue Dog Democrats.

The day's floor schedule was filled with question marks in the places where there should be the announced timing of votes.

With Republicans lockstep opposed to the president's big plan, deriding it as slide to socialist-style spending, Biden as been hunkered down at the White House reaching for a deal with members of his own party for a signature legislative accomplishment. 

The president canceled a planned trip to Chicago where he was to discuss the importance of COVID-19 vaccines, met separately with Manchin and Sinema at the White House and even showed up at Wednesday evening's annual congressional baseball game, a gesture of goodwill during the rare bipartisan event among lawmakers.

Still, Biden has been unable to bring is vaunted negotiation skills to bear and close the deal on what would be a once-in-a-generation package, as much as $3.5 trillion on health care, education and climate change initiatives all paid for by higher taxes on corporations and the wealthy.

Thursday's vote has been seen as a pressure point on the senators and other centrist lawmakers to strike an agreement with Biden as they chisel away at the size of the package. But with Manchin and Sinema dug in, that seemed unlikely.

"I think it's pretty clear we're in the middle of a negotiation and that everybody's going to have to give a little," said White House press secretary Jen Psaki.

At the same time, Congress is starting to resolve a more immediate crisis that arose after Republicans refused to approve legislation to keep the government funded past Thursday's fiscal yearend and raise the nation's debt limit to avoid a dangerous default on borrowing.

The Senate is poised to vote Thursday to provide government funding to avoid a federal shutdown, keeping operations going temporarily to Dec. 3. The House is expected to quickly follow. 

The debt ceiling debate shifts to October, ahead of another deadline when Treasury Department has warned money would run out to pay past bills.

As Biden and his party struggle to strike accord on broader package, Democrats are poised to trim the $3.5 trillion tax proposals and spending goals to reach an overall size Manchin and Sinema are demanding.

Together, Manchin and Sinema are two senators holding the keys to unlocking the stalemate over Biden's sweeping vision, the heart of his campaign pledges. While neither has said no to a deal, they have yet to signal yes — but they part ways on specifics, according to a person familiar with the private talks and granted anonymity to discuss them.

Manchin appears to have fewer questions about the revenue side of the equation — the higher taxes on corporations and the wealthy — than the spending plans and particular policies, especially those related to climate change that are important to his coal-centric state. He wants any expansion of aid programs to Americans to be based on income needs, not simply for everyone.

Though Sinema is less publicly open in her views, she focuses her questions on the menu of tax options, including the increased corporate rate that some in the business community argue could make the U.S. less competitive overseas and the individual rate that others warn could snare small business owners.

Biden insists the price tag actually will be zero because the expansion of government programs would be largely paid for with higher taxes on corporations and the wealthy — businesses earning more than $5 million a year, and individuals earning more than $400,000 a year, or $450,000 for couples.