WASHINGTON - Turning back the latest, and potentially most threatening, attack on Roe vs. Wade, a deeply divided Supreme Court struck down for the first time yesterday a state law that bans "partial-birth" abortions."
In a 5-4 ruling that cast doubt on most such laws now on the books in 31 states and that endangers an effort in Congress to pass similar legislation, the court nullified a Nebraska law because the measure could outlaw the most common forms of abortions.
Bans on "partial-birth" abortions generally seek to forbid any abortion that includes a partial removal of the fetus from the womb as part of the process. Because part of the fetus is brought outside the uterus before the fetus has died, supporters of such a ban say the procedure involves a "partially born" child, and they liken it to infanticide.
Efforts to outlaw the procedure have drawn strong support not only among legislators but also in public opinion surveys, and have been viewed - by both sides in the abortion debate - as the most serious threat yet to a woman's constitutional right to end her pregnancy. That right was established by the Roe decision in 1973.
Closing its current term with an emotionally charged recital of its differences over a variety of social issues, the court also ruled 6-3 that pregnant women who travel to and from abortions clinics have a constitutional "right to be let alone" that bars anti-abortion protesters from approaching them too closely.
The court's decision against the Nebraska ban was its first ruling on abortion rights in eight years - since a ruling in 1992 partly reaffirmed Roe vs. Wade and a woman's right to seek an abortion.
Justice Stephen G. Breyer, who was not on the court then, wrote the new ruling. The majority refused to reconsider Roe and reaffirmed strict constitutional limits on the states and Congress when they try to pass anti-abortion laws.
No law that seeks to bar an abortion procedure, the majority stressed, will be upheld if it bans a procedure that is supported as safe by "a significant body of medical opinion" and if it forbids that method to be used even when a doctor deems it the safest one for a patient.
Breyer noted that medical opinion is divided on the safety of some forms of "partial-birth" abortions. But he said such opinion did not have to be unanimous for the procedure to be constitutionally protected.
The ruling appears to leave the states and Congress with at least a narrow opportunity to try to draft new abortion bans. But new laws would be permitted only if they narrowly and specifically banned one rarely used method - the so-called "D&X" procedure - and only if that method remained available for use by doctors who considered it the safest one for a particular patient.
That opportunity emerged most clearly as a result of a separate opinion by Justice Sandra Day O'Connor. Because her vote was necessary to form the five-member majority, her views - somewhat more encouraging to anti-abortion forces than Breyer's opinion - might turn out to be decisive in future cases.
But considering how the existing 31 state laws are worded, many of them might fail under either the Breyer or O'Connor approach, because many do not include an exception when use of the procedure was necessary to protect the health of the pregnant woman.
A similar fate may await the bills pending in Congress for a federal ban on "partial-birth" abortions - a ban that the president has twice vetoed and has said he would veto again.
Justice Clarence Thomas, in a dissenting opinion that he read in tones that flared at times with anger, said the decision would doom all such existing bans.
Clarke D. Forsythe, president of Americans United for Life, an anti-abortion group, echoed that view.
"The court," Forsythe said, "has effectively prohibited any state from redrafting their laws against partial-birth abortion laws. This is the most extreme opinion ever issued by the Supreme Court on abortion."
Simon Heller, legal director of the Center for Reproductive Law and Policy, an abortion rights group that had challenged the Nebraska law, said that "not all 31 laws are dead."
But, Heller added, "I don't think this leaves much room for legislative attack" on the procedures.
The ruling seemed to serve to reignite the debate between the two sides, whose views, Breyer noted in his opinion, are "virtually irreconcilable."
Baltimore's Cardinal William H. Keeler, chairman of the U.S. Bishops' Committee for Pro-Life Activities, said the ruling "allows not only the destruction of children inside their mothers, but children mostly outside the womb as well."
"It is a frightening development," Keeler said.
But Nancy C. Lineman, executive director of the Maryland National Abortion and Reproductive Rights Action League, said: "Thankfully, the majority of the court clearly saw that the anti-choice movement was deliberately trying to erode women's choices."