WASHINGTON — The House of Representatives has passed legislation that would provide full Social Security benefits to millions of people, moving it one step closer to becoming law.

The Social Security bill received bipartisan support in the House of Representatives on Tuesday, 327 to 75, in what is now the lame-duck period for Congress. The bill now heads to the Senate, where despite significant support, passage is not assured.

Here’s what you need to know about the legislation and what could happen next.

Decades in the making, the bill would repeal two federal policies — the Windfall Elimination Provision and the Government Pension Offset — that currently limit Social Security benefits for about 2.8 million people, according to Congressional Research Service reports.

The policy broadly limits payments to two groups of Social Security recipients: people who also receive a pension from a job not covered by Social Security, and the surviving spouses of Social Security recipients who themselves receive a government pension.

People who worked in state, local and federal government jobs have been hit hard by the policy, as have teachers, firefighters and police officers, lawmakers and advocates said.

The bill would repeal both provisions, increasing Social Security benefits for many.

The budgetary impact of the legislation is significant, adding an estimated $195 billion to federal deficits over ten years, according to the Congressional Budget Office.

That means more budget pressure on Social Security Trust funds, which were already expected to be unable to pay out all benefits from 2035. Some conservatives in the House of Representatives tried to block the legislation because of its costs.

Supporters of the bill in the House acknowledged the budget implications but said it was a matter of fairness.

“For more than 40 years, Social Security trust funds have been artificially propped up by stolen benefits that millions of Americans have paid for and that their families deserve,” said Rep. Garret Graves, R-La. and Abigail Spanberger, D-Va., the bill’s lead sponsors in the House of Representatives.

“Now is the time to put an end to this theft,” they said.

The Social Security bill has 63 sponsors in the Senate — a significant number because it requires 60 votes to pass most legislation in the chamber.

Sens. Sherrod Brown, D-Ohio, and Susan Collins, R-Maine, the lead sponsors, urged colleagues to take up the bill as soon as possible.

But the Senate has a busy agenda for the remaining weeks of the year, with government funding, disaster relief and an annual defense bill likely to take up a lot of time.

If the bill passes the Senate, it will go to President Joe Biden. If the bill is signed into law, the changes would take effect for benefits paid after December 2023.

But if the bill doesn’t pass the Senate by Jan. 3, when a new session of Congress begins, it will expire and supporters will have to start over.