President Bush has urged Congress to prohibit what abortion foes call "partial birth" abortion, and the 282-139 House vote Wednesday affirmed that the bill would be on his desk, possibly within weeks. The House must first work out minor differences with the Senate, which passed a near-identical bill in March.
The legislation, Mr. Bush said, "will help build a culture of life in America. I urge Congress to quickly resolve any differences and send me the final bill as soon as possible so that I can sign it into law."
"We have a chance today to make the world a little less cruel for the defenseless," said House Majority Leader Tom DeLay, a proponent of the legislation.
There was wide disagreement over whether the bill would survive legal challenges, how often the procedure is performed and how many abortions the bill might prevent.
But both sides concurred that the act would influence the national debate on abortion.
The legislation is modest in that it would stop relatively few abortions, said Ken Connor, president of the anti-abortion Family Research Council. But "it is monumental in that it represents the first real restriction on any form of abortion enacted into law in 30 years."
Connor said it would add to the momentum toward overturning Roe v. Wade, the landmark 1973 Supreme Court decision that established abortion rights.
NARAL Pro-Choice America president Kate Michelman said, "President Bush and anti-choice leaders in the Congress have crossed the Rubicon towards rolling back Roe."
Several abortion rights groups said they would file suit as soon as Bush signs the bill into law.
"Medical decisions should be made by doctors in consultation with their patients, not by politicians who are not qualified to make medical decisions," said Vicki Saporta, president of the National Abortion Federation.
Partial birth abortion, as defined by the bill, is a procedure in which the fetus is killed after the entire fetal head is outside the body of the mother or, in the case of breech presentation, "any part of the fetal trunk past the navel is outside the body of the mother."
It is commonly linked to a procedure medically known as dilation and extraction, in which the skull is punctured to bring about the death.
Abortion rights groups say the procedure is rare, occurring mostly in the latter stages of pregnancy when the fetus is discovered to be lethally malformed. They cite one study estimating that this type accounted for less than one-tenth of one percent of the 1.3 million abortions performed in 2000.
But Rep. Steve Chabot of Ohio, chief sponsor of the bill, put the number at up to 5,000 a year, with some performed in the second trimester when both the fetus and the mother are healthy. "It's horrific, it's barbaric, it's infanticide," he said.
Abortion rights proponents question whether a second trimester fetus can be considered viable. According to Centers for Disease Control and Prevention statistics from 48 states, most abortions (57 percent) occur within the first eight weeks of pregnancy; only 1.5 percent occur beyond the 21st week of gestation.
Some 30 states have enacted versions of "partial birth" bans, but abortion rights groups said they had been successful in court challenges in about 20 states.
The most important court decision came in 2000, when the Supreme Court, in a 5-4 ruling, struck down a Nebraska law similar to the bill moving through Congress.
The court said the law was unconstitutional because it did not provide an exception to protect the health of the mother and put an "undue burden" on the mother because the broadly written language made it unclear which procedures were banned.
According to CBS News legal analyst Andrew Cohen, the central legal question going forward is whether the language convinces the Supreme Court to change its mind.
"That question — and how it ought to be answered — is going to frame the legal debate in every courtroom and in every brief relating to this dispute," Cohen said.
"If Congress satisfactorily answered the questions the Justices had a few years ago when they stuck down a Nebraska law like this, I think this law will be upheld. If not, I think it will be ruled unconstitutional," he added.
Chabot said his bill had answered the high court's objections.
The legislation, which subjects a doctor to up to two years in prison for knowingly using the procedure, allows an exception when the life — but not the health — of the mother is at risk.
It also allows the father of the fetus to sue for damages, under certain circumstances, if a partial birth abortion is conducted.
Another question is whether the high court will have the same members when it considers the issue. Justices Sandra Day O'Connor and John Paul Stevens, who voted to strike down the Nebraska law, are considered among the most likely to retire soon, paving the way for Bush to nominate a more conservative justice.
Congress passed the measure twice and President Bill Clinton, citing the lack of a health exception, vetoed it.
In Wednesday's roll call, 220 Republicans and 62 Democrats voted "yes," while 133 Democrats, five Republicans and one independent voted "no."