tea, central to its ritual observance, that the government wants to ban as a controlled substance under federal narcotics law.

With an opinion by Chief Justice John G. Roberts Jr., the decision was one of the most significant applications of the Religious Freedom Restoration Act, a 13-year-old federal statute that requires the government to meet a demanding test before it can enforce a law in a way that creates a substantial obstacle to religious observance.

The government failed to carry its burden under the statute, Chief Justice Roberts said in an opinion that not only rejected the administration's specific arguments but also dismantled its theory of the case. The chief justice said the government's "bold argument" that the Controlled Substances Act, the basic federal narcotics law, "simply admits of no exceptions" could not be reconciled either with the religious freedom law or with administrative practice under the act itself.

For the past 35 years, he noted, the government has permitted American Indians to use peyote in their religious rituals despite the fact that peyote and its active ingredient, mescaline, are banned for general use under the Controlled Substances Act and have been found by Congress to be dangerous substances with a high potential for abuse.

Referring to the sect at issue in this case by its initials, U.D.V. (the full name is O Centro Espirita Beneficente União Do Vegetal), Chief Justice Roberts said that if peyote was permitted despite those findings "for hundreds of thousands of Native Americans practicing their faith, it is difficult to see how those same findings alone can preclude any consideration of a similar exception for the 130 of so American members of the U.D.V. who want to practice theirs."

To the government's argument that the "unique relationship" between the United States and Indian tribes justified the different treatment, the chief justice replied that "nothing about the unique political status of the tribes makes their members immune from the health risks" or other problems the government has attributed to the use of banned narcotics.

The tea, known as hoasca, is made from two plants found only in the Amazon rain forest. Its active ingredient is dimethyltryptamine, usually referred to as DMT.

The 8-to-0 decision, with Justice Samuel A. Alito Jr. not participating because he was not on the court when the case was argued Nov. 1, affirmed a preliminary injunction that two lower federal courts had granted to block further government seizures of the tea.

Followers of the church, which is based in Brazil, sued the government under the Religious Freedom Restoration Act in 1999 after customs agents seized a shipment of the tea bound for the group's American headquarters in New Mexico.

Both the federal district court in Albuquerque and the United States Court of Appeals for the 10th Circuit, in Denver, agreed that the group's 130 members were entitled to the preliminary injunction so they could maintain access to the tea while awaiting a full trial on the merits of their case. The administration then appealed to the Supreme Court.

In a technical sense, the government is still entitled to try to make its case at trial because the preliminary injunction was all that was before the Supreme Court in the case, Gonzales v. O Centro Espirita Beneficente União Do Vegetal, No. 04-1084. But the court's rejection of the government's position was so conclusive that the chance of a different outcome after a trial appears remote at best.

In his second Supreme Court opinion, Chief Justice Roberts employed a jargon-free, almost conversational style, using only two footnotes in the opinion's 19 pages. For example, he wrote at one point: "The government's argument echoes the classic rejoinder of bureaucrats throughout history: If I make an exception for you, I'll have to make one for everybody, so no exceptions."

He then went on to say that the very point of the Religious Freedom Restoration Act was to require consideration, on a case-by-case basis, of claims to religious-based exemptions from laws of general applicability.

To the government's argument that judges should not devise exceptions, Chief Justice Roberts said that the statute "plainly contemplates that courts would recognize exceptions — that is how the law works."

In a 1998 decision, the court ruled on the grounds of states' rights that the Religious Freedom Restoration Act could not be applied to the states. But the court has not questioned its applicability to the federal government.

There were also these developments, as the court returned from a four-week recess.

Military Commissions

The court deferred action on the administration's motion to dismiss a case challenging the constitutionality of the military commissions the government has established to try terrorism suspects now being held at the naval base at Guantánamo Bay, Cuba.

The justices agreed in November, over the administration's objections, to hear the case, Hamdan v. Rumsfeld, No. 05-184, and have scheduled arguments for March 28.

In December, Congress passed and President Bush signed the Detainee Treatment Act, sometimes referred to as the Graham Amendment, which removed from the federal courts jurisdiction to hear challenges brought by Guantánamo detainees to their confinement and treatment.

It is an open question whether that law divested the Supreme Court of jurisdiction to proceed with the Hamdan case. The administration is arguing that it did, while lawyers for Salim Ahmed Hamdan, the Yemeni who brought the case, argue that it did not.

The court said it would consider the issue as part of the March 28 argument, not before, and added 30 minutes to the one-hour argument for that purpose.

Job Discrimination

In an unsigned, unanimous opinion, the court ruled that the federal appeals court in Atlanta had adopted an incorrect standard in rejecting a racial discrimination lawsuit brought against Tyson Foods Inc. by two black employees.

The two men, Anthony Ash and John Hithon, sought promotions that went instead to two white men who, the plaintiffs maintained, were less qualified. A jury found for the plaintiffs.

The United States Court of Appeals for the 11th Circuit ruled for Tyson, finding that one of the men had not presented sufficient evidence of discrimination and that the company was entitled to a new trial in the other case.

A plaintiff could win such a case, the appeals court said, only when "the disparity in qualifications is so apparent as virtually to jump off the page and slap you in the face."

In vacating this ruling, the Supreme Court said the test was "unhelpful and imprecise." Without insisting on a particular formulation, the justices told the appeals court to consider other courts' approaches.

The justices also said the appeals court was incorrect to discount a Tyson manager's use of the word "boy" as possible evidence of racial discrimination. The case was Ash v. Tyson Foods, Ind., No. 05-379.

Sentencing

The court re-entered the debate it ignited six years ago over the appropriate role for judges in criminal sentencing.

It agreed to hear a case from California on whether that state's sentencing law, which presumes that judges will issue a sentence in the middle of a stated range but permits them to go higher if they state reasons, complies with the court's recent insistence that juries make the factual findings that lead to increased sentences.

The case, Cunningham v. California, No. 05-6551, could affect thousands of sentences in that state as well as in others.