It's the first federal ban on any kind of abortion since the Court established the right to an abortion in Roe vs. Wade, says CBS News correspondent Wyatt Andrews.
The 5-4 ruling said the Partial Birth Abortion Ban Act that Congress passed and President Bush signed into law in 2003 does not violate a woman's U.S. constitutional right to an abortion.
The opponents of the act "have not demonstrated that the Act would be unconstitutional in a large fraction of relevant cases," Justice Anthony Kennedy wrote in the majority opinion. He said Congress was justified in finding the procedure "similar to the killing of a newborn infant."
The ruling is huge, because the ban is now the first abortion restriction ever approved, with no exception for the health of the mother, said Andrews.
"No matter which side you are on, this is a landmark ruling in the history of abortion law in this country," CBS News legal analyst Andrew Cohen said. "The court has endorsed a federal ban that criminalizes doctors who perform this procedure even when they believe the health of the woman involved is at risk. And the ruling, I think, opens the door to future restrictions on abortion rights as well."
The decision pitted the court's conservatives against its liberals, with President Bush's two appointees, Chief Justice John Roberts and Justice Samuel Alito, siding with the majority.
Justices Clarence Thomas and Antonin Scalia also were in the majority.
"This ruling is all about Justice Samuel Alito," Cohen said. "He provided the fifth vote to uphold the federal law banning the practice and he is the reason this case came out differently than its predecessor case did. I don't think anyone on or off the court who has followed this closely believes that Sandra Day O'Connor would have okayed Congress' action here."
It was the first time the court banned a specific procedure in a case over how — not whether — to perform an abortion.
President Bush hailed the ruling, saying it affirms the progress his administration has made to defend the "sanctity of life."
"I am pleased that the Supreme Court has upheld a law that prohibits the abhorrent procedure of partial birth abortion," he said. "Today's decision affirms that the Constitution does not stand in the way of the people's representatives enacting laws reflecting the compassion and humanity of America."
Supporters of abortion rights were outraged, reports CBS News correspondent Barry Bagnato.
Even though the number of such banned abortions is small and mostly confined to the third trimester, those who sought to have the law overturned say it can now apply to thousands of second trimester abortions, when the woman's doctor thinks partial delivery is the safest course.
"This decision not only threatens women's health and the practice of medicine, and the privacy of the doctor-patient relationship, it threatens the fundamental dignity of women," said Kate Michelman, former head of NARAL Pro-Choice America.
She predicted that if President Bush gets to appoint one more justice on the court, Roe vs. Wade will be overturned.
Dr. LeRoy H. Carhart, who was plaintiff in Stenberg v. Carhart in 2000 when the Court struck down a Nebraska law banning such abortions, rued today's ruling. "When the Supreme Court considered this issue seven years ago, they agreed that women's health was a paramount concern and doctors, not politicians, were in the best position to decide what procedures were safest. What a difference seven years, a new President, and two new justices, can make."
But opponents of abortion rights say the court did the right thing.
"Certainly we saw with that horrible tragedy at Virginia Tech how tenuous life is and how valuable it is," Ann Scheidler of the Pro-Life Action League said. "Every child is important whether that child is a college student or that child is in the womb."
Abortion rights groups have said the specific procedure sometimes is the safest for a woman. They also said that such a ruling could threaten most abortions after 12 weeks of pregnancy, although government lawyers and others who favor the ban said there are alternate, more widely used procedures that remain legal.
Opponents of the ban also argue the law could apply to women like Mary Vargas, whose late-term fetus suffered kidney failure in the womb, and was fated to die. Her choice, she says, was between giving birth — where the child would suffer and die — or the kind of abortion that is now illegal.
"It's wrong for this law to exist at all," Vargas said. "Nobody could have agonized over the decision the way my husband and I did."
The outcome of today's federal ruling is likely to spur efforts at the state level to place more restrictions on abortions.