The Supreme Court turned away a state's-rights case Monday that asked whether states and their agencies must abide by a 1963 federal law requiring employers to give men and women equal pay for equal work. 

The court said for a second time it will not hear the case of a state university that wants to get out from under a class-action lawsuit filed by female professors. 

Professors Iris Varner, Teresa Palmer and Paula Pomerenke sued in 1995, alleging that Illinois State University paid female professors less than their male colleagues. 

The university claimed the professors cannot sue in federal court under the Equal Pay Act, because the law violated the state's 11th Amendment rights. 

The 11th Amendment has been interpreted to give states immunity from private suits seeking money in federal court, unless the states have consented to be sued or Congress has acted conclusively to do away with the immunity. 

The school's lawyers argued that Congress lacked the authority, and never intended, to make the law nullify states' 11th Amendment immunity. 

The female professors, backed by the Justice Department, argued that Congress was within its rights to override state immunity when it came to enforcing equal pay. 

A federal appeals court has twice agreed. 

Monday's action, taken without comment, marked the second time the case was before the high court. Last year, the justices threw out the 7th U.S. Circuit Court of Appeals decision against the university, and told the court to reconsider the case in light of a Supreme Court decision that said state employees are not protected by a federal law banning age bias. 

That age-bias decision was one in a series of 5-4 rulings that have tipped the federal-state balance of power toward the states. 

The appeals court did reconsider, and concluded that the age-bias case did not weaken the women's argument. 

The university then appealed anew to the Supreme Court, arguing that the appeals court disobeyed an order. 

Between the Illinois case's first and second visit to the high court, the justices ruled in yet another states'-rights case. 

In February, the justices narrowed the reach of the Americans with Disabilities Act by ruling state employees could not sue for money damages under the federal anti-bias law. 

The disability-rights law does not trump states' constitutional immunity against being sued for damages in federal courts, the justices said then. 

In other recent decisions limiting federal power, the court has struck down the Gun-Free School Zones Act and ruled that Congress cannot let rape victims sue their attackers in federal court. 

The current case is Illinois State University v. Varner, 00-1277.