Senate Republicans derailed a Democratic bill curbing paycheck discrimination against women, an effort that even in defeat Democrats hoped would pay political dividends in this November's congressional elections.
Wednesday's (local time) vote was 53-44 to halt Republican tactics aimed at derailing the legislation, but that fell six short of the 60 voters Democrats needed to prevail in the 100-member chamber.
The outcome on the Senate floor was not a surprise, but Democrats were playing to a wider audience.
With public opinion polls showing Democratic voters less enthusiastic than Republicans this year, Democrats aimed the measure at women, who historically lean more toward their party than men. They were also casting the issue as a crucial one for the middle class because so many families rely on female wage-earners.
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.
The bill was the latest in a campaign-year parade of measures Democrats hope will drive sympathetic voters to the polls this November. Others include proposals to extend expired unemployment benefits, raise the minimum wage and make student loans more affordable.
Senator Barbara Mikulski, a Democrat, stood up after the vote and said supporters were disappointed but that they would fight on.
This is the third consecutive election year in which Senate Democrats have pushed the bill making it harder for employers to pay women less than men in comparable jobs - and easier for aggrieved workers to sue. Republicans have shot it down each time.
"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, a Democrat.
Every voting Republican voted to block the bill. They were joined by Senator Angus King, an independent who normally sides with Democrats.
Reid's Republican counterpart faulted him for blocking Republican proposals that would cut taxes, allow more flexibility for workers' hours and take other steps they said would protect jobs and help employees. The Democratic bill would open the door for frivolous, expensive workers' lawsuits against companies, Republicans say.
"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.
The battle was suffused with the politics of an election year in which Republicans could capture Senate control and are expected to retain their hold on the House.
The bill 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.