Congressional Democrats are working during the last days of summer recess to resolve all major disputes on what will be included in the $3.5 trillion social spending package that constitutes a key piece of President Biden’s economic agenda.

Democratic lawmakers are in a time crunch to draft, vet and whip the forthcoming bill in order to move the legislation alongside the bipartisan, Senate-passed infrastructure bill, which is set for a House vote no later than Sept. 27.

According to POLITICO, Senate and House Democrats are far apart on key pieces of the package, including changes to Medicare, shoring up Obamacare, raising taxes and reducing carbon emissions. While details of the package are still taking shape, Democrats have confirmed that it will be paid for with new taxes on corporations and the wealthy, while sticking to Biden’s pledge not to raise taxes on anyone making less than $400,000 per year.

House and Senate committee chairs are trying to get on the same page this week before Congress returns but acknowledged the enormity of the task. “It is pushing it. All we can do is try,” said House Budget Committee Chair John Yarmuth (D-KY). “We’re trying to kind of pre-conference this to the greatest extent [possible].”

Senate Finance Committee Chair Ron Wyden (D-OR), who is in charge of drafting all of the tax changes in the spending package, told POLITICO the task is “a vastly bigger effort” than enacting the last COVID-19 relief package in March. That $1.9 trillion package was also passed using the same reconciliation process Democratic leaders are using to pass this social spending bill without Republican support.

After the House narrowly passed a budget plan last week needed to unlock the reconciliation process, Speaker Nancy Pelosi (D-CA) said Democratic leaders will not miss a “historic opportunity to pass the most transformative and consequential legislation for families in a century.”

“The coming weeks will be intense, but – with gratitude to Committee Chairs, Members and staff – we will achieve our goals, working with the Senate to ensure passage of our historic legislation,” Pelosi said.

House Republican leaders have labeled the Democrats’ plan as a tax-and-spending spree that will fuel inflation and send jobs overseas. “A budget is supposed to put Washington on a sustainable fiscal path and help the American people keep Congress honest about its spending,” said House Budget Ranking Member Jason Smith (R-MO). “Unfortunately, Washington Democrats are using the budget as a political tool to unleash trillions in new spending and taxes and enact misguided policies…”