THE UNITED STATES’ Supreme Court has voted to block a major sexual discrimination lawsuit against retail giant Wal-Mart – because there would be too many women seeking to take part in the case.

The court voted by 5-4, along party lines, to reverse a prior decision of the 9th Circuit Court of Appeals – finding that the 1.6 million women who would potentially take part in the class action lawsuit simply could not all have shared common ground to bring a single, aggregated case.

The case, if Wal-Mart had lost, could have seen the retailer forced to pay billions in damages over allegations that it had systematically preferred male employees for promotions and pay raises.

The majority decision, written by Justice Antonin Scalia, found that the myriad plaintiffs would have to all share common circumstances for the case to be allowed to proceed – something which was “entirely absent here”.

Justice Ruth Bader Ginsburg, of the minority, said the policy over pay and promotions was evidently “uniform throughout all stores”.

AP reported that documents lodged with the case, which dates from 2001, showed how only one in seven store managers were women, compared to 80 per cent of low-ranking supervisory jobs.

Wal-Mart had responded that women had made up two-thirds of all of its managers at that time.

The landmark decision will make it much more difficult for businesses to face class action lawsuits in future, with courts now being obliged to find a common thread among every single complainant before cases can be brought.

Opponents of the case had argued that a successful case would have allowed corporations be prosecuted for even seemingly vague complaints. The Guardian reported that Microsoft and General Electric had written to the court expressing such worries.

The defeated women bringing the cases have acknowledged that the ruling is a blow, but told AP they would continue to bring their complaints on a private, personal basis.

In a statement, Wal-Mart said it was “pleased” and satisfied the court had made the right decision.

“The Court today unanimously rejected class certification and, as the majority made clear, the plaintiffs’ claims were worlds away from showing a company-wide discriminatory pay and promotion policy,” it said.

Additional reporting by the AP