(Credit: Mark Wilson/Getty Images)

Three years after he signed it into law, President Obama has made the little-known Lilly Ledbetter Fair Pay Act the centerpiece of his re-election pitch to women.

It's a "big step toward making sure every worker in this country, man or woman, receives equal pay for equal work," Obama says in a video to supporters on his campaign blog.

The legislation repeatedly tops Obama's list of accomplishments in stump speeches on the campaign trail and is cited as a fulfilled promise from 2008.

"Change is the first bill I signed into law that enshrines a very simple proposition," Obama told a crowd of donors at the Apollo Theater Jan. 19. "You get an equal day's pay for an equal's day work."

The idea that Obama has narrowed the gender pay gap is also the subject of an aggressive digital media push to promote his record and enlist new members to the group "Women for Obama."

"Ensuring equal pay for women was @BarackObama's first act as President, but not his last," reads a message posted to the Obama for America twitter account for New Mexico, @OFA_NM.

Actress Kerry Washington, an Obama surrogate in Florida, was even more direct in a promotional video on the campaign's blog: "There's equal pay for women," she declares outright.

The only problem? Women don't enjoy equal pay, it's improved little during Obama's term and the Lilly Ledbetter Fair Pay Act has hardly been a "big step" toward the goal.

In 2010, the most recent data available, women on average earned 77.4 cents for every dollar earned by men holding the same full-time, year-round job, according to Census data analyzed by the National Committee on Pay Equity.

The gap was virtually unchanged from 2009, when it was 77 percent and 2008 when it stood at 77.1 percent, before the law was enacted.

Pay inequity remains most pronounced among women of color. African-American women made 67.7 percent of what was earned by men in 2010, according to the Census, while Hispanic women earned 58.7 percent, both figures largely unchanged from the year before.

Still, while the Lilly Ledbetter Act hasn't directly resolved the issue of systemic pay inequality, it has helped some victims of discrimination pursue their compensation claims in the courts, women's rights advocates say.

After the Supreme Court threw out Lilly Ledbetter's pay discrimination suit against her employer Goodyear Tire & Rubber Co., saying it exceeded the statute of limitations, Democrats in Congress with support from Obama enacted the law to  extend the period for alleged victims to sue.

"After the Ledbetter law was passed, we saw specific cases that had been thrown out of court - pay discrimination cases - being allowed to be brought again," said Marcia Greenberger, co-president of the National Women's Law Center. "The cases still have to be shown to be true, but at least those who believe they've been discriminated against get their day in court."

There's no way of measuring whether the legal cases have or will contribute to a broader shift in pay equality to benefit women, Greenberger conceded.

"The focus on equal pay and how to make sure the promise of the law is turned into reality is also something the administration ought to not only continue to do, as it has been, but also that a spotlight will be shined on what these efforts are," she said.

The Obama campaign has showcased Ledbetter's story with a six-minute web video documentary, an email blast to supporters relating her story and an op-ed penned by Ledbetter in major national papers in an effort to put a face on Obama's efforts for women.

Ledbetter, 73, says the law bearing her name is a reflection of Obama's commitment to equality, even if equality hasn't come quickly enough.

"It might not be such an important bill, because it just put the law back where it was," the Alabama woman told ABC News in an interview late last year. "We, per se, did not gain anything except putting it back to where it was before the ruling in my case. But it sent a strong message. And I don't think anyone has forgotten it."