The justices said they will decide the constitutionality of a 1993 law - the Religious Freedom Restoration Act - that makes it harder for government to interfere with religious practices. The court's ruling, expected by July, could clarify just when government is allowed to do so.
A church in Boerne, Texas, invoked the law after the city thwarted its attempt to build an addition. The church argued that Boerne's refusal to issue the permit was an example of governmental action banned by the law.
City officials, in turn, mounted a constitutional attack - contending that in passing the law, Congress unlawfully usurped power from state and local governments and from the Supreme Court itself.
"What's at stake is really any meaningful expression of faith for all Americans," said Melissa Rogers of the Baptist Joint Committee on Public Affairs, one of many religious groups that pushed for the act's passage.
"We think the law is both constitutional and vital to religious freedom," she said.
But the 1993 law has been particularly unpopular with prison officials in many states. They say it caused a flood of lawsuits in which inmates challenged regulation of apparel, diet and other aspects of life behind bars as violations of their religious beliefs.
In other action yesterday, the court:
n Let stand a never-enforced 1991 Michigan court order that bars Dr. Jack Kevorkian from helping people commit suicide.
n Agreed to decide in a New York case whether states may tax the income of hospitals run by employee welfare benefit plans.
n Voted to decide whether a Florida state Senate district in the Tampa-St. Petersburg area unlawfully favors black voters.
n Ordered a federal appeals court to reconsider a ruling that had barred California's use of poison gas in executions.
The 1993 law on religious freedom was enacted in response to a 1990 Supreme Court decision that said laws otherwise neutral toward religion are not unconstitutional just because they may infringe on some people's religious beliefs.
The 1990 decision came in an Oregon case about Native American rituals. The court found there is no constitutional right to take the hallucinogenic drug peyote as a religious practice.
A broad coalition of religious and civil rights groups contended that the court, in the rationale it used in the peyote case, had turned its back on vigorously protecting religious rights. And Congress agreed.
The resulting 1993 legislation required that any federal, state or local law imposing a "substantial burden" on someone's religious beliefs must serve a "compelling" government interest in the least intrusive way.
That standard lets government protect public health and safety but also gives religious minorities far more legal clout.
Boerne's sweeping attack against the 1993 law called it "a bold and unprecedented example of federal social policy engineering."
The city's lawyers said the law violates the 10th Amendment rights of states and local governments by forcing them to allow more protection for religious beliefs than the Constitution requires.
They also contended that the law violates the separation of powers by forcing federal courts to impose a more exacting standard than the Supreme Court said was necessary in its 1990 ruling.
Sixteen states joined in a friend-of-the-court brief supporting the city. They said the federal law has disrupted prison life by allowing "gangs and like-minded groups to shroud illicit activity under the cover of 'religious' belief."
The states are Delaware, Florida, Hawaii, Idaho, Illinois, Iowa, Minnesota, Mississippi, Nevada, New Hampshire, North Carolina, Ohio, Oklahoma, Pennsylvania, South Dakota and Vermont.
The Texas dispute granted review stems from space problems at the St. Peter Catholic Church in Boerne.
The church, part of the San Antonio Archdiocese, applied for a permit in 1993 to enlarge its 70-year-old building. The church has more than 2,000 members but its sanctuary can accommodate fewer than 250 at one time.
In 1991, the church building's facade was placed in the city's historic district. A city landmark commission in 1993 rejected the church's request to enlarge the building even though a proposed addition would not affect the facade.
The church sued, and a federal appeals court upheld the 1993 law. In other disputes around the country, however, courts have ruled it unconstitutional.