Justices, on a 6-3 vote, said that a federal drug law does not override the 1997 Oregon law used to end the lives of more than 200 seriously ill people.John Roberts backed the Bush administration, dissenting for the first time.
CBS News legal analyst Andrew Cohen calls the ruling a "significant defeat for the Bush Administration, which had fought hard to convince the Court that the federal laws governing doctors should have trumped Oregon's suicide law."
The administration improperly tried to use a drug law to punish Oregon doctors who prescribe lethal doses of prescription medicines, the court majority said.
"Congress did not have this far-reaching intent to alter the federal-state balance," Justice Anthony M. Kennedy wrote for himself, retiring Justice Sandra Day O'Connor and Justices John Paul Stevens, David Souter, Ruth Bader Ginsburg, and Stephen Breyer.
Kennedy is expected to become a more influential swing voter after O'Connor's departure. He is a moderate conservative who sometimes joins the liberal wing of the court in cases involving such things as gay rights and capital punishment.
The ruling was a reprimand to former Attorney General John Ashcroft, who in 2001 said that doctor-assisted suicide is not a "legitimate medical purpose" and that Oregon physicians would be punished for helping people die under the law.
Kennedy said the "authority claimed by the attorney general is both beyond his expertise and incongruous with the statutory purposes and design."
Justice Antonin Scalia, writing for himself, Roberts and Justice Clarence Thomas, said that federal officials have the power to regulate the doling out of medicine.
"If the term 'legitimate medical purpose' has any meaning, it surely excludes the prescription of drugs to produce death," he wrote.
Scalia said the court's ruling "is perhaps driven by a feeling that the subject of assisted suicide is none of the federal government's business. It is easy to sympathize with that position."
Oregon's law covers only extremely sick people, those with incurable diseases and who are of sound mind, and after at least two doctors agree they have six months or less to live.
"For Oregon's physicians and pharmacists, as well as patients and their families, today's ruling confirms that Oregon's law is valid and that they can act under it without fear of federal sanctions," state Solicitor General Mary Williams said.
"This ruling will encourage other people in other states who may have been contemplating similar assisted-suicide laws to go ahead and get them on the books — and as long as those other laws are similar to the Oregon law they ought to pass the constitutional test," Cohen says. "And I wouldn't be surprised if these efforts begin immediately."
The ruling backed a decision by the 9th U.S. Circuit Court of Appeals, which said Ashcroft's "unilateral attempt to regulate general medical practices historically entrusted to state lawmakers interferes with the democratic debate about physician-assisted suicide."
Ashcroft had brought the case to the Supreme Court on the day his resignation was announced by the White House in 2004. The Justice Department has continued the case, under the leadership of his successor, Attorney General Alberto Gonzales.
The court's ruling was not a final say on federal authority to override state doctor-assisted suicide laws, only a declaration that the current federal scheme did not permit that. However, it could still have ramifications outside of Oregon.
White House press secretary Scott McClellan said the Justice Department had immediately begun a review of what the impact might be. "We are disappointed at the decision," he said. "The president remains fully committed to building a culture of life, a culture of life that is built on valuing life at all stages."
"This is a disappointing decision that is likely to result in a troubling movement by states to pass their own assisted suicide laws," said Jay Sekulow, chief counsel of the American Center for Law and Justice, which backed the administration.
Sen. Ron Wyden, D-Ore., and a supporter of the law, said the ruling "has stopped, for now, the administration's attempts to wrest control of decisions rightfully left to the states and individuals."
Thomas wrote his own dissent as well, to complain that the court's reasoning was puzzling. Roberts did not write separately.
Justices have dealt with end-of-life cases before. In 1990, the Supreme Court ruled that terminally ill people may refuse treatment that would otherwise keep them alive. Then, justices in 1997 unanimously ruled that people have no constitutional right to die, upholding state bans on physician-assisted suicide. That opinion, by then-Chief Justice William H. Rehnquist, said individual states could decide to allow the practice.
Roberts strongly hinted in October when the case was argued that he would back the administration. O'Connor had seemed ready to support Oregon's law, but her vote would not have counted if the ruling was handed down after she left the court.
The case is Gonzales v. Oregon, 04-623.