Washington ? The Supreme Court declared Monday that white firefighters in Connecticut were unfairly denied promotion because of their race, ruling against minorities in a major reverse discrimination case that could affect bosses and workers nationwide. The justices threw out a decision that high court nominee Sonia Sotomayor had endorsed as an appeals court judge.

In its last session until September, the court’s conservative majority prevailed in a 5-4 ruling that faulted New Haven and the courts that had upheld the city’s discarding of results of an exam in which no African-Americans scored high enough to be promoted to lieutenant or captain.

The city said it acted to avoid a lawsuit from minorities, but Justice Anthony Kennedy said in his majority opinion that New Haven’s action amounted to discrimination based on race against the white firefighters who were likely to be promoted.

“No individual should face workplace discrimination based on race,” Kennedy said.

The ruling restricts, but does not eliminate, employers’ ability to take diversity into account in employment decisions. But the ruling could make it harder for minorities to prove discrimination based solely on lopsided racial hiring or promotions.

Sotomayor and two appeals court colleagues had ruled the city did the right thing in throwing out the test, and the Supreme Court reversal gave critics fresh ammunition two weeks before her Senate confirmation hearing. Conservatives said it showed her to be a judicial activist who lets her own feelings color her decisions.

“This case will only raise more questions in the minds of the American people concerning Judge Sotomayor’s commitment to treat each individual fairly and not as a member of a group,” said Sen. Jeff Sessions, R-Ala.

On the other hand, the Obama administration and liberal allies said her stance in the case demonstrated her restraint and unwillingness to go beyond precedents established by her own 2nd U.S. Circuit Court of Appeals in New York.

The high court ruling shows “she doesn’t legislate from the bench,” said presidential spokesman Robert Gibbs. “The Supreme Court clearly had a new interpretation of Title VII of the Civil Rights Act.”

Coincidentally, the justices may have given a boost to calls for quick action on her nomination.

The court said it would return Sept. 9 to hear a second round of arguments in a campaign finance case, and with Justice David Souter retiring there would be only eight justices unless Sotomayor has been confirmed by then.

In Monday’s ruling, Kennedy said, “Fear of litigation alone cannot justify an employer’s reliance on race to the detriment of individuals who passed the examinations and qualified for promotions.” He was joined in the majority by Chief Justice John Roberts and Justices Samuel Alito, Antonin Scalia and Clarence Thomas.

In dissent, Justice Ruth Bader Ginsburg said the white firefighters “understandably attract the court’s empathy. But they had no vested right to promotion and no person has received a promotion in preference to them.”

Justices Souter, Stephen Breyer and John Paul Stevens signed onto Ginsburg’s dissent, which she read aloud in court Monday. Speaking dismissively of the majority opinion, she predicted the court’s ruling “will not have staying power.”

Labor and employment lawyers suggested that companies that act to encourage and preserve racial, gender and age diversity would need to be very careful to avoid reverse discrimination lawsuits.