Washington (AFP) - The Republican-led US Senate approved President Donald Trump’s mammoth domestic policy bill Tuesday by the narrowest of margins, despite misgivings over delivering deep welfare cuts and another $3 trillion in national debt.

Republican leaders had struggled to corral support during a record 24-hour “vote-a-rama” amendment session on the Senate floor, as Democrats offered dozens of challenges to the most divisive aspects of the package.

But Senate Majority Leader John Thune was able to turn around wavering moderates to deliver a 50-50 vote, with Vice President JD Vance breaking the tie.

The sprawling text now heads to the House of Representatives, where it faces unified Democratic opposition and multiple Republicans balking at the budget-busting costs, as well as slashed health care and food aid programs for poor Americans.

Trump’s bill proposes a $4.5 trillion extension of his first term tax cuts, contentiously offset with $1.2 trillion in savings mainly targeting the Medicaid health insurance program, as well as federal food aid.

The health care cuts could see an estimated 12 million low-income and disabled Americans lose coverage.

The package also rolls back billions of dollars in green energy tax credits while providing a $350 billion infusion for border security and Trump’s mass migrant deportation program.

The president made clear that the goal remains to get the bill through the House in the coming days and sign it into law by Friday’s July 4 Independence Day holiday.

“It’s going to get in, it’s going to pass, and we’re going to be very happy,” Trump told reporters ahead of the vote.

- ‘Utter shame’ -

Polls show the bill is among the most unpopular ever considered, and Democrats hope to leverage public anger ahead of the 2026 midterm elections when they aim to retake the House.

Backed by extensive independent analysis, they say the bill’s tax cuts would disproportionately benefit the wealthy at the expense of social safety net programs for the poorest Americans.

“Today, Senate Republicans betrayed the American people and covered the Senate in utter shame,” said Chuck Schumer, the leader of the Senate Democratic minority.

“In one fell swoop Republicans passed the biggest tax break for billionaires ever seen – paid for by ripping away health care for millions of people and taking food out of the mouths of hungry kids.”

A handful of senators in the Republican majority had threatened to upset the apple cart, voicing concerns that the bill would add more than $3.3 trillion to the nation’s already yawning budget deficits over a decade.

The most high-profile opposition came in the shape of tech billionaire and estranged former Trump aide Elon Musk, who balked at the bill’s debt implications and stripping of clean energy subsidies.

A furious Trump on Tuesday said he would consider deporting Musk – whose electric car company Tesla gives him extensive interests in green energy – and ending federal funds for his companies.

“Elon may get more subsidy than any human being in history, by far, and without subsidies, Elon would probably have to close up shop and head back home to South Africa,” Trump posted on social media.

- Focus on House -

Although the House of Representatives has already passed its own version of the bill, it will have to come back to the lower chamber for a final rubber stamp before it reaches Trump’s desk.

House Republicans were watching anxiously from the sidelines to see if their Senate colleagues would adopt changes that would be hard for Speaker Mike Johnson to sell to his lawmakers.

Fiscal hawks in the lower chamber are furious at what they say is $651 billion of extra deficit spending in the Senate’s tweaks.

A House vote could come as early as Wednesday but even with full attendance, House Republicans can only afford to lose three votes.

“The House will work quickly to pass the One Big Beautiful Bill that enacts President Trump’s full America First agenda by the Fourth of July,” Johnson said after the vote.

“The American people gave us a clear mandate, and after four years of Democrat failure, we intend to deliver without delay.”