WASHINGTON — The nonpartisan Congressional Budget Office said on Thursday evening that President Biden’s sprawling climate change and social policy package would increase the federal budget deficit by $160 billion over the next 10 years.
That determination is at odds with Mr. Biden’s pledge to fully pay for the legislation but is unlikely to stop House Democrats from approving the bill as soon as Thursday evening.
The budget office’s analysis found that the bill’s tax cuts and spending programs were almost — but not entirely — offset by new revenue and spending cuts. The package would be largely paid for with tax increases on high earners and corporations, which was estimated to bring in nearly $1.5 trillion over 10 years. Savings in government spending on prescription drugs were estimated to bring in another $260 billion.
The fact that the bill could slightly add to the federal deficit over the next 10 years is unlikely to dissuade House lawmakers from proceeding to vote for the bill, in part because the analysis boiled down to a dispute over a single line item: how much the Internal Revenue Service would collect by cracking down on people and companies that dodge large tax bills.
The budget office predicted that beefing up the I.R.S. with an additional $80 billion of funding would bring in just $127 billion over 10 years. That is far less than the $400 billion the White House estimates it would bring in over a decade, both through enforcement actions and by essentially scaring tax cheats into paying what they owe.
Democrats, who have stuffed the bill with long-desired priorities and policy changes, took turns on Thursday highlighting the bill’s array of environmental provisions, an expansion of health care and support for education and child care.
“We have a chance to redefine our commitment to the American people and to move toward a more just, equitable and perfect union,” said Representative Jimmy Gomez, Democrat of California.
Ms. Pelosi talked up the areas of agreement that Democrats had reached in both the House and Senate: universal prekindergarten, generous assistance with child care costs, prescription drug price controls and home health care for older Americans.
Senator Ron Wyden of Oregon, the Democratic chairman of the Senate Finance Committee, dismissed the budget office’s analysis of how much the I.R.S. could catch from tax cheats and said that he agreed with the Treasury Department’s rosier projection.
“I’m confident in the Treasury Department’s estimate, which is backed up by experts and I.R.S. Commissioners appointed by Republican and Democratic presidents,” he said in a statement.
Moderate Democrats, whose deficit concerns have delayed a House vote on the bill, have signaled they are likely to side with the administration’s view.
“I think we’re all well aware that there’s going to be a discrepancy around the I.R.S. piece and let’s just reserve judgment until we see the whole package,” Representative Stephanie Murphy, Democrat of Florida, said earlier this week.
Such views could pave the way for the plan to clear the House in a final vote as soon as Thursday evening.