Click photo to enlarge
Plaintiff Betty Dukes stands outside the Supreme Court in Washington, Tuesday, March 29, 2011, after attending a case of women employees against Wal-Mart. (AP Photo/Jacquelyn Martin)

WASHINGTON -- The Supreme Court on Monday blocked a massive sex discrimination lawsuit against Wal-Mart on behalf of female employees in a decision that makes it harder to mount large-scale bias claims against the nation's biggest companies.

The justices all agreed that the lawsuit against Wal-Mart Stores Inc. could not proceed as a class action in its current form, reversing a decision by the 9th U.S. Circuit Court of Appeals in San Francisco. By a 5-4 vote along ideological lines, the court said there were too many women in too many jobs at Wal-Mart to wrap into one lawsuit.

The lawsuit brought by Pittsburg Wal-Mart worker Betty Dukes, Concord Sam's Club worker Christine Kwapnoski and four others could have involved up to 1.6 million women, with Wal-Mart facing potentially billions of dollars in damages.

In a statement, Wal-Mart said, "The court today unanimously rejected class certification and, as the majority made clear, the plaintiffs' claims were worlds away from showing a companywide discriminatory pay and promotion policy."

Dukes and Kwapnoski said they were disappointed in the ruling, but vowed to push ahead with their claims.

"This is just one defeat in a bunch of victories. It doesn't mean the war's over," Dukes said. "We still are poised to present our case in court. We believe it's still very much alive and viable."

"All I have to say is when I go back to work tomorrow, I'm going to let them know we are still fighting," Kwapnoski said during a conference call on Monday.

Brad Seligman of Impact Fund, the attorney representing Dukes, agreed that the case is not over.

"We will have to develop some different strategies, but Wal-Mart is not off hook," added Brad Seligman of Impact Fund, the attorney representing Dukes.

Dukes, 61, witnessed the hourlong oral arguments in Washington, D.C., and was photographed on the Supreme Court steps with her legal team. She returned to work at the Pittsburg Wal-Mart, where she has been a greeter for 17 years. Kwapnoski is an assistant manager at Sam's Club, which is owned by Wal-Mart Stores.

Marcia D. Greenberger, co-president of the National Women's Law Center, said, "The court has told employers that they can rest easy, knowing that the bigger and more powerful they are, the less likely their employees will be able to join together to secure their rights."

The high court's majority agreed with Wal-Mart's argument that being forced to defend the treatment of female employees regardless of the jobs they hold or where they work is unfair.

Justice Antonin Scalia's opinion for the court's conservative majority said there need to be common elements tying together "literally millions of employment decisions at once."

But Scalia said that in the lawsuit against the nation's largest private employer, "That is entirely absent here."

Justice Ruth Bader Ginsburg, writing for the court's four liberal justices, said there was more than enough uniting the claims. "Wal-Mart's delegation of discretion over pay and promotions is a policy uniform throughout all stores," Ginsburg said.

Business interests lined up with Wal-Mart while civil rights, women's and consumer groups have sided with the women plaintiffs.

Both sides have painted the case as extremely consequential. The business community has said that a ruling for the women would lead to a flood of class-action lawsuits based on vague evidence. Supporters of the women feared that a decision in favor of Wal-Mart could remove a valuable weapon for fighting all sorts of discrimination.

Said Greenberger: "The women of Wal-Mart, together with women everywhere, will now face a far steeper road to challenge and correct pay and other forms of discrimination in the workplace."

The lawsuit, citing what are now dated figures from 2001, said that women are grossly underrepresented among managers, holding just 14 percent of store manager positions compared with more than 80 percent of lower-ranking supervisory jobs that are paid by the hour. Wal-Mart responded that women in its retail stores made up two-thirds of all employees and two-thirds of all managers in 2001.

The company also has said its policies prohibit discrimination and that it has taken steps since the suit was filed to address problems, including posting job openings electronically.

Paul Burgarino of the Contra Costa Times contributed to this report.