With midterm elections looming, Democrats are pitching themselves as the party of fairness for one of their key voting blocs: women.
"When women succeed, America succeeds," President Barack Obama said Tuesday in remarks to commemorate Equal Pay Day and urge Congress to pass more legislation to close the gender pay gap.
Responding to critics who say the gender gap in pay has been overstated, Obama stated bluntly "It's not a myth; it's math."
Obama also signed two executive orders on Tuesday intended to narrow the gap between wages for women and men in the federal contracting workforce. One would prevent federal contractors from punishing workers who discuss their salaries; the other will require them to submit data about how they compensate employees of different sexes and races.
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The president's pitch is accompanied by a communications full-court press by Democratic lawmakers and groups hoping to highlight what they say is a significant wage gap between men and women. (The latter supported Obama by a 55 percent to 44 percent margin in the 2012 election.)
Democrats cite data that has found that the real median earnings of men and women who work full-time and year-round for the same amount of time show a female-to-male earnings ratio of 0.77, or 77 cents on the dollar.
But critics of that methodology argue that the 77 cents calculation does not account for differences like preferences for job flexibility, risk level, education and hours worked weekly.
Republicans hold that they also support "equal pay for equal work" but that Democrats are putting too much emphasis on market regulations rather than job growth. And they warn that more legislation could lead to frivolous lawsuits.
"What we're promoting as Republicans are those policies that are going to empower women and everyone, give people freedom and flexibility, jobs, higher paychecks and the opportunity for a better life," said Rep. Cathy McMorris Rodgers, R-Wash., during a press conference Tuesday.
Republicans have also pointed to a January study that showed female members of Obama's own staff make only 88 cents for every dollar a male staff member earns.
GOP lawmakers are poised to block Democratic attempts to pass the Paycheck Fairness Act this week, which would apply Tuesday's executive order reforms to the workforce at large.
—By Carrie Dann of NBC News