Sen. Susan Collins could cast a pivotal vote on a sweeping budget bill being pushed by President Donald Trump and congressional Republicans that would extend tax cuts, boost border security and strip health care coverage and food support from millions of Americans.

The Senate debated amendment through Monday night and into Tuesday morning. A vote is expected Tuesday, but it’s not yet clear whether Republicans have secured the necessary support. Vice President JD Vance was at the Capitol and prepared to cast a deciding vote in case of a 50-50 tie.

Collins voted over the weekend to advance the bill to the Senate floor. The procedural motion cleared the Senate by a single vote, setting the stage for a full day of amendment proposals from both sides of the aisle.

But she has not committed to supporting it when it comes up for a final vote and has called for changes, including increased taxes on the super-wealthy and protection for rural hospitals that could be threatened by Medicaid cuts. Other Republicans holdouts are seeking their own concessions in the bill, which would add more than $3 trillion to the national deficit over the next decade and cut clean energy spending.

“I support the tax relief in the bill for working families and small businesses,” Collins said in a written statement Monday afternoon, as the Senate continued to vote on a series of amendments to the bill. “The Medicaid provisions, as they stand, are problematic, particularly for people who live in rural Maine and our hospitals and nursing homes. I also oppose the new excise tax and other burdensome provisions on energy projects, producers, and consumers. We have many more amendments to go through and debate to be had before we vote on final passage.”

Collins and Sen. Lisa Murkowski, R-Alaska, were among the potential Republican swing votes being closely watched as the debate continued.

With Democrats united against the bill, Republicans can only afford to lose three votes from their members. And two Republican senators, Sens. Rand Paul, R-Ky., and Thom Tillis, R-N.C., have already announced their opposition.

Collins, who faces reelection next year, has made it clear that her procedural vote over the weekend to advance the bill did not necessarily mean she will support its passage. “If the bill is not further changed, I would be leaning against the bill,” Collins said on Saturday.

Collins has publicly expressed concerns about a nearly $1 trillion cut in Medicaid and how it could threaten the financial stability of rural hospitals. But she also told reporters in Washington, D.C., that, even if the Senate included $100 billion in additional funds to protect rural hospitals from the impact of Medicaid cuts, she still would have reservations.

Collins planned to offer at least one amendment on Monday — to increase taxes on the super-wealthy and increase funding for rural hospitals. She proposed adopting a 39.5% tax on income over $50 million for married couples and over $25 million for individuals. The current rate is 37%. And she proposed adding $25 billion in funding for rural hospitals, for a total of $50 billion, which is still only half of what she originally called for.

Paul and Tillis were the only Republican senators to vote against advancing the bill over the weekend. Tillis later announced he would not seek reelection.

Republicans can afford to lose one additional vote Monday, which would allow Vice President JD Vance to break a tie and vote for passage. Two more Republican defections would kill the bill.

National and local Democratic groups were eager to highlight Collins’ vote to advance the bill, which they have condemned as cutting health insurance for millions of Americans to pay for tax cuts for millionaires.

Maeve Coyle, spokesperson for the Democratic Senatorial Campaign Committee, said in a written statement Monday that Collins’ procedural vote to advance the bill while at the same time expressing concerns about it showed why she’s been called a reliable vote for her party.

“Collins has once again made clear that when faced with a choice, she will always side with Trump and Washington Republicans over Mainers — and Mainers will hold her accountable by voting her out in 2026,” Coyle said.

Sen. Angus King, an independent who caucuses with the Democrats, has been vocal in his opposition to the bill, saying it will result in 60,000 Mainers losing health coverage and prompt already struggling rural hospitals to reduce services for everyone, or close entirely, which recently happened in Waterville.

“I’ve been in this business of public policy now for 20 years, eight as governor, 12 years in the United States Senate,” King said in a floor speech Sunday night. “I have never seen a bill this bad. I have never seen a bill that is this irresponsible, regressive, and downright cruel.”

King has advocated for maintaining only the tax breaks for families who earn $400,000, while allowing those for wealthier families to expire, which he said would result in a 60% savings and would not require the roughly $1 trillion cut in Medicaid.

“Let’s kill it, give it a merciful death over the next 24 hours, and then start over writing a responsible bill to deal with the expiring tax cuts for the middle class and deal with issues within the federal government that should be addressed,” King said in his floor speech. “But this bill is not the answer. It is a sham. And it is a shame. And it’s embarrassing to even be debating this bill.”

Republicans released details of the 940-page budget reconciliation bill — dubbed the “One Big Beautiful Bill Act” — on Friday night, and voting began over the weekend. Senate Democrats forced a full reading of the bill on the floor.

Republicans are hoping to meet a self-imposed deadline of sending the bill to Trump’s desk by Friday.

If approved, the budget would have to go back to the House, which passed its own version of the bill on June 22, with both Rep. Jared Golden, D-2nd District, and Rep. Chellie Pingree, D-1st District, opposed.

The version advanced by the Senate contains steeper cuts to Medicaid and would add an additional $1 trillion a year to the deficit.

A new analysis from the nonpartisan Congressional Budget office Sunday estimates the Senate bill would increase the deficit by nearly $3.3 trillion from 2025 to 2034, a nearly $1 trillion increase over the House-passed bill. It also found that 11.8 million more Americans would become uninsured by 2034, more than with the House’s approach.

The bill also includes a $5 trillion increase in the debt ceiling.

Material from the Associated Press was used in this report.