The Paycheck Fairness Act, which would have strengthened equal pay opportunity laws for women, failed to clear the Senate Nov. 17.

The bill would have amended portions of the existing Equal Pay Act of 1963, and would have made wage discrimination based on sex unlawful.

The Senate narrowly rejected the act by a vote of 58-41. The bill needed 60 to move forward. Over a year ago, the legislation passed the House by significant margins.

House Speaker Nancy Pelosi, D-Calif., blamed partisan politics.

“Republican Senators stood against fundamental fairness for America’s working women and families struggling to get by; with a parliamentary tactic, they have prevented the Paycheck Fairness Act from moving forward,” Pelosi said in a statement. “But the problem remains: women are still earning just 77 cents for every dollar men make. And in this time of great economic challenge, that difference in pay makes a big difference for families.”

Last year, women who worked full-time earned median weekly wages that were 80 percent of men’s. They earned $657 compared to men’s $819, according to the Bureau of Labor Statistics. The ratio of women-to-men earnings crested at 81 percent since the Labor Department began comparing earnings in 1979. That peak came in 2005 and 2006.

Opponents of the Paycheck Fairness Act said it was too stringent and would have prevented employers from justifying legitimate pay differences.

“Some women may get pay increases, but what is going to happen is inevitably you will move toward a very rigid civil-service-like pay system, and there won’t be any opportunity for significant merit-based raises,” Lawrence Lorber, a Proskauer Rose LLP labor law expert, told The Wall Street Journal. “What you will have to do is assure that when you give increases you don’t wind up with some sort of a pay differential, and you do that by not giving pay increases or by creating superficial promotions.”

The act would have held employers to a more limited defense against charges of wage discrimination, and required employers to report pay data based on sex, race, national origin, among other measures.

According to a statement released by the White House a day before the vote, President Obama supported the amendment.

“The persistent gap between men’s and women’s wages demonstrates the need for legislative change,” Obama said Nov. 16 . “This bill would address this gap by enhancing enforcement of equal pay laws.”