Republicans in the U.S. Senate blocked the passage of the Paycheck Fairness Act on Tuesday, rejecting the measure intended to protect women from pay discrimination.

The vote, 52 to 47 in favor, was strictly along party lines. Two Independent senators, Joe Lieberman of Connecticut and Bernard Sanders of Vermont, voted along with Democrats in favor of its passage while Sen. Mark Kirk, R-Ill., who is recovering from a stroke, did not vote, according to The Hill. The legislation fell short of the 60 votes it needed for cloture, which would have then allowed a full, time-limited Senate debate and then a standard up-or-down vote.

I say to the women out there in America, let's keep this fight going. Put on your lipstick, square your shoulders, suit up and let's fight for a new American revoultion where women are paid equal pay for equal work, and let's end wage discrimination in this century once and for all, said Sen. Barbara Mikulski, D-Md., the bill's chief sponsor, in a rousing speech on the Senate floor after the measure failed.

The legislation aimed to increase workplace protections for women by closing loopholes in the landmark Equal Pay Act of 1963. The bill -- which also died in the Senate at the hands of a Republican-led filibuster two years ago -- would have expanded the statute of limitations for women suing for pay discrimination, required that employers prove that pay discrepancies between male and female workers in the same position are not based on sex, and created a federal grant program to help women improve their salary negotiation skills.

Senate Republicans argue the measure would not strengthen previous laws fighting gender pay discrimination and have even suggested it would be harmful for small businesses, because they would be more vulnerable to employee lawsuits.

Republicans, who insist they oppose compensation discrimination based on gender, introduced their own alternative to the Paycheck Fairness Act on Tuesday. Like the Democratic bill, The End Pay Discrimination Through Information Act, sponsored by Sen. Dean Heller, R-Nev., would ban employers from firing workers who inquire about salaries to determine gender discrimination. But it would not allow the federal government to collect salary information to monitor pay differences or provide the federal grant program for women.

Let me be clear, pay discrimination based on gender is unacceptable, Heller said Tuesday, before the vote. Despite the political rhetoric around here, everyone agrees on this fact. The question is, will the Paycheck Fairness Act actually address workplace inequality? And the simple answer is no.

While the federal government purportedly banned gender wage discrimination almost 50 years ago with the passage of the Equal Pay Act, the U.S. Census reports that women still earned, on average, 77 cents on every dollar brought in by a man. The Center for American Progress reports the average female workers lose about $434,000 in salary or wages compared with men over the course of her careers.