CLASS ACTIONS have been and should remain important tools to combat employment discrimination. These legal vehicles allow a small number of often brave individuals to step forward to assert grievances against their employer. These “named plaintiffs” act as proxies for a multitude of others who may have experienced similar harm. This strength-in-numbers approach can give workers the needed leverage to stop discriminatory practices or demand wages they were unfairly denied.

A class action against Wal-Mart Stores, filed nearly 10 years ago, aimed to address alleged discrimination against female employees who were denied equal pay or unfairly overlooked for promotions. Six women initially came forward; a California federal trial judge eventually allowed the suit to proceed on behalf of “all women who have worked at Wal-Mart since 1998.” Roughly 1.5 million current and former female employees could be affected.

On Tuesday, the Supreme Court took up the Wal-Mart case to determine whether it should be allowed to advance. It is a close call, but on balance we think it should not in its current form.

The federal rules that govern class actions require that members of the class share “questions of law or fact [in] common”; they also require that “the representative parties will fairly and adequately protect the interests of the class.” Lawyers for the plaintiffs argue that female employees have been hurt by the company’s policy of giving managers on the local level almost unfettered discretion in personnel decisions. But if this discretion is nearly absolute, then how could the company itself be held accountable for an allegedly discriminatory nationwide policy that affects some 3,400 stores?

The diversity of the class in terms of geography and job type also raises concerns. The class includes part-time, hourly employees and salaried managers. Of the 120 or so affidavits submitted by women alleging to have been wronged, more than half came from six states; there were no claims of wrongdoing in 14 states where employees would nevertheless be included in the class action.

Fairness to all of the women involved is also an issue. Because of the way the lawsuit was crafted, the unnamed plaintiffs have had no say over whether they want to be part of the litigation. If the case proceeds as is, these women will be unable to vindicate their rights in the future, even if they have a stronger case — and stronger prospects for compensation — than the original named plaintiffs.

The court may well decide that the class as currently structured is not workable. In that case, the justices should give the women a chance to more narrowly tailor the class. They should also consider allowing individuals the opportunity to opt out. But in no case should they rule in a manner that would thwart the chances of having the women’s grievances addressed.