The largest class action suit in U.S. history was grounded to a halt by the nation’s highest court on Monday. The case, regarding former female Wal-Mart employees who alleged they were discriminated against based on their gender, had major implications for other large U.S. employers.

The key argument of the legal action was based on statistical evidence about pay discrepancies between male and female workers, and also on case-by-case instances of alleged workplace discrimination. However, the court ruled that the women had failed to demonstrate common “questions of law or fact” that held for all the women in the proposed class (any woman who has worked for one of more of 3,400 Wal-Mart stores in the United States since December 1998).

“Here, [the group of women employees] wish to sue about literally millions of employment decisions at once,” according to a written statement by Justice Antonin Scalia.

“Because respondents wish to sue about literally millions of employment decisions at once, they need some glue holding the alleged reasons for all those decisions together, it will be impossible to say that examination of all the class members’ claims for relief will produce a common answer to the crucial question ‘why was I disfavored,’” wrote Scalia.

The gravity of the combined cases would have been more powerful in terms of impacting corporate America as well as compensation claims, but the Supreme Court has dismissed the joint class action.

The world’s largest retailer, Arkansas-based Wal-Mart, may still be vulnerable, so rather than combine their efforts to tackle the courts, it may now be possible for each individual case to be examined.

The lawsuit was originally filed in 2001 by Betty Dukes—a store greeter in Pittsburg, Calif.—along with five of her co-workers.

She claimed that her six-year track record of good performance reviews did not enable her to gain training to be promoted to a more senior role.

According to Wal-Mart’s legal counsel, the testimony of the key witness of the plaintiff, a sociologist name William Beilby, “could not estimate what percentage of Wal-Mart employment decisions might be determined by stereotypical thinking,” the court’s opinion says.

“His testimony was worlds away from ‘significant proof’ that Wal-Mart ‘operated under a general policy of discrimination.’”

Wal-Mart’s lawyer Theodore Boutrous Jr. of Gibson, Dunn & Crutcher said, “Once their expert admitted that he couldn’t tell what percentage of the employment decisions were determined by stereotyped thinking that destroyed the class certification argument,” according to a BBC report.

Court Dismisses Sex Discrimination Suit Against Wal-Mart