(CNN) - Senate Republicans on Wednesday blocked a Democratic-backed proposal that aims to even the pay gap between men and women.
GOP members argued there are already laws against pay discrimination and the "paycheck fairness act" would lead to government interference in the workplace.
Republicans tried to offer multiple amendments, but Democrats refused to promise votes.
The measure now stalled in the Senate would have no chance of making it through the Republican-led House regardless.
The pay equity bill is one of a series of pocketbook issues Democrats are promoting ahead of the midterm elections this fall.
President Barack Obama is also promoting the issue this week, having called the income disparity between genders an "embarrassment."
On Tuesday, he highlighted so-called pay secrecy, which is the idea that women who are paid less than male coworkers may not know it because they don't know what other employees make.
Obama signed executive orders prohibiting federal contractors from retaliating against employees who discuss their pay and requesting new requirements for contractors to submit summaries of pay data, including a breakdown of sex and race.
Democratic strategists see equal pay as a way to galvanize the base and raise money for midterms that historically see less turnout and excitement than a presidential election year.
By keeping the issue in the news, Democrats hope to benefit in the long term by showcasing GOP presidential hopefuls who oppose equal pay protections.
According to CNN national exit polls, Democrats won the female vote 56%-43% in the 2008 presidential election and by 55%-44% in Obama's 2012 reelection.
But the GOP narrowly edged out the Democrats among women 49%-48% in the 2010 midterms, when Republicans, thanks to a landslide 63-seat pick up, won back the House, and made a major dent in the Democrats' Senate majority.
Many in the GOP see laws like the paycheck fairness measure as an effort to help trial lawyers mount cases. Republican Sen. Rand Paul of Kentucky said it would interfere with the free market.
CNN's Ted Barrett and Paul Steinhauser contributed to this report.