After losing the women’s vote in November, the White House and congressional Democrats will be watching the Supreme Court closely next spring when it hears an appeal by Wal-Mart in a class-action employment-discrimination case.

The issue at stake is not about gender-discrimination; rather, the focus is whether or not the case can move forward based on the commonality of the class. While two lower courts — most recently the United States Court of Appeals for the 9th Circuit, in San Francisco — ruled that the case could go forward, the dissenting opinions raised some serious concerns about why it should not.

Chief Judge Alex Kozinski in California was clear in his dissent that the plaintiffs “have little in common but their sex and this lawsuit.” He was referring to the fact that other than being women, the 500,000 employees in the class worked at Wal-Mart stores throughout the 50 states, at different levels of the corporation, and had a range of different supervisors (both men and women).

While the appeal is about the class, women’s activists are ready to blame a conservative court for an unfavorable outcome. Adam Cohen of Time argued today that the high court’s “conservative majority has used legal technicalities” to prevent “valid civil rights and civil-liberties claims.”

But Cohen oversimplifies. The agreement to hear Wal-Mart’s appeal is about a lot more than procedure. The assumption by the plaintiffs is that Wal-Mart has a company-wide practice of gender-discrimination — of paying women less and promoting them less quickly than their male counterparts. If that’s the case, then it seems justified to ensure the class is certifiable in its commonality.

Certainly there are bad employers out there and discrimination still occurs. But too often the left clings to claims of gender-discrimination and the wage gap and refuses to consider alternatives that might explain differences in pay. When you don’t just look at the raw data, but you control for any number of variables, the wage gap all but disappears. In the end, differences in pay appear to be more a function of individual choices than of prejudice. (Even a recent report for the Department of Labor makes this same conclusion.)

If SCOTUS stops the case, it’s not because they support pay discrimination. But if the case moves forward, it’s not necessarily the best thing for women. The fact is, cases like this and gender-protection legislation increase the cost of employing women. And that’s something everyone in favor of women’s rights ought to think about.