President Donald Trump’s budget mega-bill has cleared a major hurdle and is one step closer to becoming law.

The bill, known as the One Big Beautiful Bill Act, narrowly passed the Senate on Tuesday and is set to be considered by the House of Representatives on Wednesday.

The legislation has stoked disputes over the deficit, social programmes and spending levels within the Republican Party, which controls both chambers of Congress.

The Senate required Vice-President JD Vance to cast the tie-breaking vote to pass the bill and its prospects in the House appears similarly precarious. The legislation has seen several iterations, and a previous version cleared the House last month by just a single vote.

The new bill would make permanent large tax cuts that were temporarily put in place when President Trump was first in office, and increases spending for border security, defence and energy production.

To make up for the expected loss of revenue, Republicans have looked to cut spending in a wide range of programmes, including food subsidies and health insurance coverage for lower-income Americans.

The Congressional Budget Office estimates the bill would add $3.3tn to federal deficits over the next 10 years and leave millions without health coverage, a forecast that the White House disputes.

Congressional Republicans are racing to pass the bill ahead of a self-imposed 4 July deadline in order to send it to Trump’s desk for signing into law.

Here’s a look at some of its key items.

On the campaign trail, Trump vowed to eliminate taxes on Social Security income – monthly payments to Americans of retirement age and people with disabilities.

The House bill fell short of delivering on that promise, but it did temporarily increase the standard deduction of up to $4,000 for individuals 65 and over. That deduction would be in place from 2025-28.

Senate Republicans approved an extension of Social Security tax breaks and an increase that would grant a $6,000 tax deduction for older Americans who earn no more than $75,000 a year.

To help finance tax cuts elsewhere, Republicans have added additional restrictions and requirements for Medicaid, the healthcare programme relied upon by millions of disabled and low-income Americans.

Changes to Medicaid – one of the biggest components of federal spending – has been a major source of political strife.

One of the changes are new work requirements for childless adults without disabilities. To qualify, the bill says, they would be required to work at least 80 hours per month from December 2026.

Another proposed change to the programme is requiring Medicaid re-enrolment to shift from once a year to every six months. Enrolees would also have to provide additional income and residency verifications.

The Senate proposal puts even more restrictions on Medicaid, which is likely to cause more headaches for Republicans in the House.

The upper chamber’s version proposes to lower provider taxes – which states use to help fund their share of Medicaid costs – from 6% to 3.5% by 2032.

Complaints from some Republicans in states that draw funding from these taxes, especially for rural hospitals, led the Senate to delay the cuts and add a $50bn rural hospital fund.

The Senate bill also proposes tightening eligibility requirements so that able-bodied adults with children aged 15 and over would need to work or volunteer at least 80 hours a month.

The Senate Medicaid work requirement is said to be the strictest ever proposed by Republicans, raising the odds that large numbers of Americans could lose medical coverage as they will not keep up with the new paperwork.

The bill increases the deduction limit for state and local taxes (Salt).

There is currently a $10,000 cap on how much taxpayers can deduct from the amount they owe in federal taxes. That expires this year.

The Senate’s approved bill raises it from $10,000 to $40,000 – but after five years, it would return to $10,000.

Salt taxes were a big sticking point in the House, especially Republican holdouts in some Democratic-controlled urban areas. The House’s version of the spending bill did not include a five-year limit, so the Senate’s changes could pose a problem for some House Republicans.

Reforms have also been added to the Supplemental Nutrition Assistance Program (Snap), which is used by over 40 million low-income Americans.

The Senate bill requires states to contribute more to the programme, which is currently fully funded by the federal government.

The government would continue to fully fund the benefits for states that have an error payment rate below 6%, but states with higher error rates would be on the hook for anywhere from 5% to 15% of the programme’s costs.

The change would start in 2028.

The Senate bill also adds work requirements for able-bodied Snap enrollees who do not have dependents.

The “no tax on tips” provision in the budget bill would mark a win for one of Trump’s promises during the campaign.

The Senate bill being considered by the House would allow individuals to deduct a certain amount of tip wages and overtime from their taxes. However, they propose gradually phasing out those benefits based on annual income, starting at $150,000 for individuals and $300,000 for joint filers.

It would expire in 2028.

The Senate legislation would also permanently increase a child tax credit to $2,200 – which is $300 less than what House lawmakers had eyed. The House version required both parents have a Social Security number, but the Senate OK’d a requirement of only one parent.

The upper chamber’s bill also proposes raising the debt ceiling by $5tn – more than the $4tn approved by the House last month. The debt ceiling is the limit on the amount of money the US government can borrow to pay its bills.

Lifting the debt limit allows the government to pay for programmes already approved by Congress.

One of the most notable divisions between House and Senate Republicans is the Senate’s proposal for clean energy tax breaks.

Although both call for an end to the Biden-era federal clean energy tax credits, Senate Republicans approved phasing them out more slowly.

For instance, the Senate has extended the runway for businesses that build wind and solar farms to still benefit from the tax credits. However, both the House and Senate version seek to deny the credits to companies whose supply chains may have ties to a “foreign entity of concern”, such China.

Companies that begin construction this year could qualify for the full tax break. That drops to 60% if they begin construction in 2026 and 20% if they begin in 2027. The credit would disappear in 2028.

The House version of the bill sought to end the tax breaks for those companies almost immediately.

The Senate approved version of this bill is scheduled to come before the House on Wednesday, though it’s unclear when a vote might happen.

Some House Republicans have already expressed issues with the legislation and the changes made by the Senate.

Chip Roy from Texas said the Senate’s proposal on clean energy was “not close to enough”. Other hard-line Republicans in the House Freedom Caucus have voiced concern over increases to the national debt.

“The House was clear: no new deficit spending. The Senate isn’t listening – their version adds over $1T to the deficit, completely ignoring the House framework,” Texas congressman Keith Self said. “This isn’t just reckless – it’s fiscally criminal.”

Trump has repeatedly urged Republicans to get on board. He asked House Republicans to unite, ignore “grandstanders” in the party and send “this bill to my desk”.

“We are on schedule – Let’s keep it going, and be done before you and your family go on a July 4th vacation,” he wrote on Truth Social. “To my GOP friends in the House: Stay UNITED, have fun, and Vote ‘YAY.'”

Democrats, who have neither a majority in the House nor Senate, have criticised the bill, particularly on changes to Medicaid and food stamps.

House Minority Leader Hakeem Jeffries called it a “reckless, regressive and reprehensible GOP tax scam” and pledged to use the bill against Republicans in next year’s Midterm elections.