A Democrat-backed bill aimed at curbing paycheck discrimination against women failed to clear a key Senate hurdle on Wednesday, as Republicans blocked the measure amid concerns from business groups.
The bill fell short on a 53-44 vote. It needed 60 to advance.
It was the third consecutive election year in which Senate Democrats have pushed the bill and Republicans have shot it down.
The bill's rejection was widely expected, yet Democrats hope the effort will pay political dividends in this November's congressional elections. They are trying to drive up turnout this fall by women, who historically lean more Democratic than men.
The bill would make it harder for employers to pay women less than men in comparable jobs, and easier for aggrieved workers to sue.
Democrats say the bill is needed to help address the persistent gap between what men and women make. "For reasons known only to them, Senate Republicans don't seem to be interested in closing wage gaps for working women," said Senate Majority Leader Harry Reid, D-Nev.
But Republicans accused Democrats of simply trying to score political points at the expense of businesses.
Republicans, with strong backing from the U.S. Chamber of Commerce and other business groups, said the measure would tie the hands of employers.
"It's time for Washington Democrats to stop protecting trial lawyers and start focusing on actually helping the people we were sent here to represent," said Senate Minority Leader Mitch McConnell, R-Ky.
Republicans said the bill would make it hard for companies to award merit pay or offer flexible work hours in exchange for lower pay and expose employers to costly, frivolous lawsuits.
McConnell cited statistics showing how women's income has fallen and their poverty rate increased under Obama.
Every voting Republican voted to block the bill. They were joined by Sen. Angus King, I-Maine, who normally sides with Democrats.
As if to underscore the political sensitivity of the debate, McConnell held his usual Tuesday session with reporters accompanied only by Sen. Deb Fischer, R-Neb., who was pushing a narrower version of the legislation. Typically, McConnell faces the cameras joined by the top members of the Senate GOP leadership, who are all men.
At almost the same time, a parade of Democratic female senators trooped to the Senate floor to defend the bill.
The bill by Sen. Barbara Mikulski, D-Md., would narrow the factors businesses can cite for paying women less than men in the same jobs, and bar employers from retaliating against workers who share salary information. It also would make it easier to bring class-action lawsuits against companies and let victors in such lawsuits win punitive and compensatory damages.
Paycheck discrimination based on gender has been illegal since the 1960s. The Ledbetter law extended the time people have to file lawsuits claiming violations of that law.
Women averaged 77 percent of men's earnings in 2012, according to Census Bureau figures. That is better than the 61 percent differential of 1960, but little changed since 2001.
While few deny workplace discrimination exists, politicians and analysts debate its impact on women's earnings.
Data shows that men tend to out-earn women at every level of education and in comparable jobs.
Yet women generally work shorter hours and are likelier to take lower-paying jobs. Sixty-two percent of the 3.3 million workers earning at or below the minimum wage last year were women, according to the federal Bureau of Labor Statistics.
The Associated Press contributed to this report.