Senator Barbara Milkulski is holding a press conference later today to press the Senate to pass the Paycheck Fairness Act, which she recently introduced. But didn’t President Obama already kill the gender wage gap? Not quite. While Obama has long been touting the first bill he signed once in office, the Lilly Ledbetter Fair Pay Act, it only provides a woman more time to file a claim of discrimination. The Paycheck Fairness Act would go further by ensuring employees can discuss their salaries with each other—since it’s hard to root out pay discrimination if you don’t know how you stack up against everyone else.

Lilly Ledbetter certainly helps women who want to bring lawsuits against their employers by giving them more time to do so. In that way, Obama’s first act did recognize the problem of pay discrimination. But it’s a baby step forward in the march toward equal pay.

The numbers since its signing bear that out. According to Bloomberg, the number of pay discrimination complaints filed with the Equal Employment Opportunity Commission actually fell from 2,268 when Obama signed the Act in 2009 to 2,191 last year. Meanwhile, the pay gap has widened from 77.8 in 2007 to 77.4 percent in 2010.

So what will it take to make the wage gap disappear? Why wouldn’t clearing the way for lawsuits get us there? Part of the answer is that Ledbetter only nibbled at the edges of an enormous, systemic problem. As I’ve previously written, the causes of the gap range from a too low minimum wage to decreased unionization levels. These kinds of issues won’t budge on a large scale even if women are emboldened to sue for equal pay.

But can lawsuits make way for a big cultural shift on how we view and deal with discrimination? Perhaps it’s worth looking at another workplace issue that got a lot of legal attention not too long ago: sexual harassment. It’s far from a thing of the past: over 11,000 charges were filed with the EEOC and local Fair Employment Practices agencies last year. That’s down substantially from the late ’90s, however, which saw numbers in the 15,000s. And we’re a long way from the Mad Men era, when sexual harassment in the workplace was par for the course. “The women who brought some of the original lawsuits lived in war zones. Sometimes their lives were destroyed before they got out,” E.J. Graff, contributing editor at The American Prospect, senior fellow at the Schuster Institute for Investigative Journalism at Brandeis University and collaborator on Evelyn Murphy’s book Getting Even: Why Women Still Don’t Get Paid Like Men—And What To Do About It, told me. “I was just shocked by what I learned when I interviewed them and read the testimony.” It’s hard to deny that we’ve seen a huge cultural change in how we view that kind of discrimination.

How did that come about? Lawsuits certainly played a big part. While Title VII of the Civil Rights Act stipulated that an employer can’t discriminate on the basis of sex, it wasn’t until cases like Meritor Savings Bank v. Vinson that it was established that sexual harassment falls under such protection. Even after that, though, the Supreme Court then had to lay out the framework for making such claims. That didn’t happen until the ’90s—meaning that sexual harassment cases have been having a significant impact for only two decades.

And it may not have been an individual woman’s ability to file claims of discrimination per se that brought about the change but the effect of large, headline-grabbing suits on the culture at large. An individual woman may not even benefit. “A sexual harassment lawsuit itself doesn’t really help the person who brings it. She may end up with some money, but the process can ruin her life,” said Graff. “But does it change the climate for the next woman? Does it alert employers and prompt them to change their policies? Sometimes.”

One of the big turning points, according to Michelle Caiola, a senior staff attorney at Legal Momentum and former senior trial attorney at the EEOC, was the EEOC v. Mitsubishi suit of 1998. That case had an impact because it was so large—300–400 class members, a $34 million settlement and rampant, egregious harassment. Those aspects made headlines, which made all the difference. “Whenever a sexual harassment lawsuit gets a lot of media attention, I think that’s what starts the cultural shift,” she told me. “The media attention informs the employees of what is acceptable or what is not acceptable or what their legal rights are. I also think it brought home to employers that this was a very serious issue they could suffer both in reputation and having to pay out monetarily.”

Then, of course, came Anita Hill’s testimony of sexual harassment at Clarence Thomas’s confirmation hearings, which played a huge part. After her 1991 testimony, the EEOC reported that sexual harassment cases more than doubled over the next five years, from 6,127 to 15,342, and awards to victims under federal laws nearly quadrupled from $7.7 million to $27.8 million. It took a media frenzy to get case numbers up significantly, not just the ability to file them.

Can the gender pay gap get the same kind of media attention if cases move forward? Would things like the Lilly Ledbetter Act, which help women bring those cases, have an impact if they allow for those kinds of suits? Potentially, although there is a crucial difference. “The one thing that sexual harassment has going for it that it’s about sex,” Caiola said. She added bluntly, “Pay equity is not as sexy.” It may be a harder task to get the media circus hyped up about equal pay than about a suit over the coercion of sexual favors.

And those cases aren’t having a lot of success lately. The most recent high-profile case was the one brought against Wal-Mart by cashier Betty Dukes, which alleged a widespread culture of gender discrimination there. The suit was on behalf of 1.5 million women—certainly making for a high-impact case that could have shifted cultural views on wage discrimination. But the Supreme Court threw out the case last summer, arguing that the women didn’t qualify as a single class.

So the answer is mixed. The ability for women to bring suits is certainly important, and we need steps forward like Ledbetter—as opposed to steps backward, as seen recently in Wisconsin—to keep up that momentum. But it may not be until some high-profile cases hit the headlines that we experience significant cultural change.