President Joe Biden attends a virtual COVID-19 summit during the 76th Session of the United Nations General Assembly, in the South Court Auditorium on the White House campus, Wednesday, Sept. 22, 2021, in Washington. (AP Photo/Evan Vucci)

WASHINGTON (AP) — Time growing shorter, President Joe Biden launched meetings Wednesday with House and Senate Democrats as Congress worked to bridge party divisions over his big “build back better” agenda ahead of crucial voting deadlines.

The back-to-back afternoon sessions at the White House come at a pivotal juncture for Biden’s $3.5 trillion package as lawmakers struggle to draft the ambitious effort. With Republicans solidly opposed, Democratic leaders are counting on the president to galvanize consensus between progressives and centrists in their party.

Biden was conferring first with House Speaker Nancy Pelosi and Senate Majority Leader Chuck Schumer, and the White House’s communications team headed to Capitol Hill to huddle with other House Democrats.

“The time is now,” Biden tweeted in a video Tuesday ahead of the White House sessions.

The House faces a deadline Monday to vote on the first part of Biden’s plan — a nearly $1 trillion public works measure that was already approved by the Senate but has become tangled in disputes over the broader package.

Centrist Democrats support the slimmer bill but have raised concerns about Biden’s broader vision — which entails revamping federal taxes and spending to make what the president views as overdue investments in health care, family services and efforts to fight climate change.

The $3.5 trillion package would impose tax hikes on corporations and wealthy Americans earning beyond $400,000 a year and plow that money back into federal programs for young and old, along with investments to tackle climate change.

House Speaker Pelosi has promised centrists a vote on the more modest $1 trillion public works package. That bill of roads, broadband and public water projects enjoys bipartisan Senate support and should easily pass the House even with growing House Republican opposition, but has become sidelined by the bigger debate.

“I’m confident we’ll have the votes,” said Rep. Josh Gottheimer, D-N.J., a leader of the centrist coalition who is attending the White House meeting.

But progressive lawmakers view the public works bill as inadequate and plan to vote against it unless it is considered alongside the bigger Biden package.

Some 50 members of the Congressional Progressive Caucus plan to vote against the bipartisan measure.

Rep. Pramila Jayapal, D-Wash., chairwoman of the progressive caucus, emerged from an hour-long meeting with Pelosi late Tuesday saying its position had not changed and the two bills must move “in tandem” to win the progressive votes. Jayapal also will attend the meeting with Biden.

Publicly, the White House has remained confident both bills will pass, and Democratic leaders are pushing ahead as they draft the details.

Tensions are high as the Biden agenda is a key campaign promise not only from the president but most of the the Democratic lawmakers, including those in the House who face re-election next year.

All told, more than 20 lawmakers were invited to confer with Biden, moderates and progressives in separate meetings stretching into the evening, making their best pitches. Key centrist Sens. Joe Manchin of West Virginia and Kyrsten Sinema of Arizona, were to be among them.

Despite disputes, many Democrats are saying they expect the final product to align with Biden’s broader vision and eventually have robust party support, even if that version is adjusted or scaled back.

“These are really popular things,” said Rep. John Yarmuth, of Kentucky, chairman of the Budget Committee.

At the Capitol, Biden’s communications director Kate Bedingfield unfurled a 24-page presentation to House Democrats, much of it focused on the potential economic benefits and popularity of the package with voters, according to a person granted anonymity to discuss the private session.

But underscoring the job ahead, Rep. Debbie Dingell, D-Mich., told her colleagues that “none of that matters unless we get it done,” the person said.

Meanwhile, another deadline looms. The House and Senate are at a standstill over a separate package to keep the government funded past the Sept. 30 fiscal yearend and suspend the federal debt limit to avert what could be a devastating U.S. default on payments.

The government faces a shutdown if funding stops on Sept. 30, the end of the fiscal year. Additionally, at some point in October the U.S. risks defaulting on its accumulated debt load if its borrowing limits are not waived or adjusted.

Rushing to prevent that dire outcome, the Democratic-led House passed the funding-and-debt measure Tuesday night, but Republicans are refusing to give their support in the Senate, despite the risk of triggering a fiscal crisis.

Senate Republican leader Mitch McConnell has said since Democrats control the White House and Congress, it’s their problem to find the votes — though he had relied on bipartisan cooperation to approve debt limit measures when Republicans were in charge.

The administration has sent intermediaries including former Treasury Secretary Hank Paulson to meet with McConnell of Kentucky, to no apparent avail.

“They have an obligation to raise the debt ceiling and they will do it.” McConnell said Tuesday.

The measure approved Tuesday night would provide stopgap money to keep the government funded to Dec. 3 and extend borrowing authority through the end of 2022. It includes $28.6 billion in disaster relief for the aftermath of Hurricane Ida and other extreme weather events, and $6.3 billion to support Afghanistan evacuees in the fallout from the end of the 20-year war.

The Senate is likely to vote Monday. But in the 50-50 Senate, Democrats will be hard-pressed to find 10 Republicans to reach the 60-vote threshold needed to overcome a filibuster. Other options to try to pass the debt ceiling package could be procedurally difficult.

The Treasury Department projects that at some point next month it will run out of cash reserves. That could force it to delay or miss payments, an outcome experts warn could ripple negatively through an economy still battered by the COVI-19 crisis.