The Biden administration is preparing a massive spending proposal on infrastructure and other domestic priorities like child care and drug costs that could put fights over hot-button issues like climate change and taxes front and center.

A source familiar with the plans confirmed that administration officials are eyeing $3 trillion as the topline figure for its Build Back Better jobs and infrastructure proposal, though they cautioned talks are fluid and the final number could change. The sweeping package would constitute the White House’s follow-up to the $1.9 trillion economic relief measure signed into law earlier this month.

The new package is expected to be split into two separate bills. The first would focus on infrastructure, with spending on manufacturing and climate change measures, broadband and 5G, and the nation’s roads and bridges.

The other measure would include funds for pre-K programs, free community college tuition, child tax credits and health care subsidies, according to multiple reports.

The White House declined to confirm details of the proposal, saying nothing had been finalized.

"President Biden and his team are considering a range of potential options for how to invest in working families and reform our tax code so it rewards work, not wealth,” White House press secretary Jen Psaki said in a statement Monday. “Those conversations are ongoing, so any speculation about future economic proposals is premature and not a reflection of the White House's thinking.”

The administration has signaled for weeks that it planned to tackle infrastructure after getting the COVID-19 relief bill across the finish line. The issue has generally received bipartisan support, and President Biden has already met with members of both parties to discuss a potential deal.

But there’s daylight between Democrats and Republicans on how to pay for such a package.

Republicans have balked at tax increases, particularly amid the pandemic. Biden has previously voiced support for raising the corporate tax rate to 28 percent. The rate was lowered from 35 percent to 21 percent under a 2017 tax-cut law. Progressives are also likely to push for tax increases on wealthy Americans, which polling suggests is supported by a majority of the country.

The approaching fight could force the White House and Senate Democrats to make critical choices in how to move forward. Democrats will be forced to choose between budget reconciliation, which requires only a simple majority in each chamber for passage, or securing at least 10 GOP votes in the 50-50 Senate.

Sen. Joe Manchin (W.Va.), an influential moderate Democrat, has signaled he would like to work through regular order to pass an infrastructure package.

Looming over the upcoming talks are the increasing calls from Democrats to modify or do away with the legislative filibuster, which requires 60 votes in the Senate to move forward with a bill.

“I think they’re going to try to give regular order a try, and they’re going to see what negotiations look like before definitely making a decision about how they want to proceed in the end,” said Shai Akabas, director of economic policy at the Bipartisan Policy Center.

“I think moderates have made pretty clear that they’re not ready to totally get rid of the filibuster, so it seems like if that’s the case they need to find 10 or more Republicans who are willing to negotiate with them or find a way that ... you can get unanimity within the Senate Democratic Caucus and close to unanimity in the House Democratic Caucus,” he added.

“Both are uphill battles, so I don’t think there’s an easy path.”

Some progressive groups already have come out to argue Biden should not be held back by efforts to appeal to Republicans.

“Biden must not cower to fears of losing bipartisanship — Republicans have already made clear they’re not interested in working with Democrats — and must deliver an infrastructure package that meets the scale of this moment,” Ellen Sciales, a spokesperson for the Sunrise Movement, said in a statement. “If Republicans or archaic Senate rules get in the way, Democrats must abolish the filibuster and deliver for the American people.”

Administration officials have been careful not to get ahead of themselves as they chart a path forward.

Psaki has on multiple occasions declined to dive into the specifics of what a Build Back Better legislative proposal would look like, nor has she waded into whether such a package would pass through reconciliation.

“[Biden’s] preference and his priority is working with Democrats and Republicans to find a pathway forward on a range of issues where there has been a history of bipartisan support, whether it's infrastructure, immigration, addressing — making our economy and our workers more competitive against — against the competition with China,” Psaki told The Hill at a briefing last week when asked about Biden’s view on the filibuster.