• House lawmakers have reached the number of signatures they need to prompt a vote on a bill that would eliminate certain rules that reduce Social Security benefits for pensioners.
• The Social Security Fairness Act would repeal rules known as the Windfall Elimination Provision, or WEP, and the Government Pension Offset, or GPO.
• The bipartisan bill has wide support in both the House and the Senate.

House lawmakers in Washington have the signatures they need to force a vote on a bill to eliminate rules that reduce Social Security benefits for certain retirees who also receive pension income.

On Thursday morning, Reps. Abigail Spanberger, D-Va., and Garret Graves, R-La., marked the 206 signatures a discharge petition had thus far collected with a press conference outside the Capitol building alongside organizations representing police, firefighters, postal workers, teachers and other government employees often affected by those rules.

By Thursday afternoon, the number of signatures had climbed to 218, enough to force a vote on the bill.

The bipartisan bill — the Social Security Fairness Act — would repeal rules known as the Windfall Elimination Provision, or WEP, and the Government Pension Offset, or GPO, that currently reduce Social Security benefits for almost 3 million Americans.

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"We have taken on, on a bipartisan basis, something that's just completely unjust, that has been going on for over four decades," Graves said.

"This is a situation where you have some of the most important occupations, some of the most important contributors to our community, that are being discriminated against," he said.

How WEP, GPO rules affect retirement decisions

The Windfall Elimination Provision reduces Social Security benefits for individuals who receive pension income from public roles that did not contribute Social Security payroll taxes — but who also paid into the program and qualified for benefits through other work. The WEP affects about 2 million Social Security beneficiaries.

The Government Pension Offset, meanwhile, reduces spousal benefits for federal, state or local government employees who did not contribute to Social Security payroll taxes. The GPO affects almost 800,000 retirees.

The rules can force affected workers to make tough retirement decisions.

That includes Lois Carson, president of the Ohio Association of Public School Employees, who said during Thursday's press conference that the rules affected the decisions she made to support her family after her husband passed away. While Carson was able to receive income from his pension, she was not able to access Social Security survivor benefits, as she and her husband both worked as public employees.

"I continue to work after 37 years, because if I retire, I'm going to lose half of my funding because of this law," Carson said.

Carson said a friend lost the $1,200 monthly Social Security benefit checks she received on her husband's record after she retired from her job as a public school employee.

Bill faces uncertainties despite bipartisan momentum

The bill to repeal the WEP and GPO rules is the "most bipartisan and co-sponsored bill in the United States Congress," Rep. Greg Landsman, D-Ohio, said Thursday.

The House version of the bill currently has 327 co-sponsors.

If the bill is put up for a vote in the House, it may pass, experts say.

Then it would go to the Senate, where the bill has 62 co-sponsors.

Time constraints may limit the effort's progress, Emerson Sprick, associate director for the Bipartisan Policy Center's economic policy program, recently told CNBC.com.

"Both the Senate and the House have a lot of work to do before the end of the year," Sprick said.

While experts agree the WEP and GPO rules could be adjusted to be fairer, some say eliminating them altogether may not be the answer.

The Congressional Budget Office has estimated the move would cost around $196 billion over 10 years. Social Security already faces a trust fund shortfall, with the program's combined funds projected to run out in 2035, when 83% of benefits will be payable.

Others have voiced concerns that repealing the rules would result more a more generous income replacement formula for workers with combined public and private work compared with others who contribute to Social Security for their entire careers.

"To the extent that people have worked both in covered and non-covered employment, in general they should be receiving some Social Security benefit," said Paul Van de Water, a senior fellow at the Center on Budget and Policy Priorities.

"The question is how much," he said.