A bill that confers legal rights to a fetus by making it a separate crime when an unborn child is killed in a violent act against its mother passed the House Thursday, but the measure's fate in the Senate is much less clear.

The Unborn Victims of Violence Act (search) passed the House 254-163. It has the strong endorsement of the White House and was near the top of the election-year wish list for President Bush's conservative base. Opponents of the measure say the bill brings America one step closer to outlawing abortion.

Already, 29 states have laws that make it a separate crime when the fetus is harmed during an attack on a pregnant woman. Some states even define the death of a fetus as murder.

One of those states is California, where Scott Peterson (search) is on trial for the murder of his wife Laci and their unborn son Conner. The Unborn Victims of Violence Act has also been designated Laci and Conner's Law (search).

"My family is grateful that under California law, the murders of Laci and Conner can both be prosecuted. But for the families of many other murder victims across the country, there can be no such comfort. Federal law does not recognize that these crimes have two victims," Laci's mother Sharon Rocha (search) said before the final vote.

Laci Peterson's murder isn't the only case of a pregnant woman whose unborn child was also lost in the violence, say supporters.

"Too many pregnant women are being victimized by criminals, and the current law does not reflect the reality that when a criminal harms the woman, that criminal is also harming the unborn child," said House Speaker Dennis Hastert.

Carol Lyons' 18-year-old daughter Ashley was murdered in January. She was 21 weeks pregnant and had just hours earlier returned from an ultrasound that showed her she had a son, whom she immediately named Landon.

The assailant, who is still unknown, shot Ashley Lyons three times. She and the baby both died.

"We lost two family members, not just one. And that's why we support this law," said Carol Lyons, who came to Washington from Kentucky with her husband Buford in order to lobby for Laci and Conner's law.  

Democratic opponents to the bill say the real aim of the legislation is to undermine abortion rights by giving the unborn the same legal rights as the born. They charge that abortion politics is taking precedence over the need to protect abused women.

"If the fetus is recognized as a legal person, then this bill would open the door to barring abortions, to prosecuting women or to restraining them physically for the sake of the fetus," said Rep. Jerold Nadler, D-N.Y.

But in 2000, Nadler and other opponents of the bill voted for a different House bill that prohibited executing any pregnant prisoner. That bill's definition of an unborn child is "a member of the species homo sapiens, at any stage of development, who is carried in the womb" — exactly the same as the one used in the bill named after Laci and Conner Peterson.

"I fail to see what the distinction is," said Rep. Melissa Hart, R-Pa., the bill's primary sponsor, who added that the bill specifically precludes from prosecution doctors who perform legal abortions.

The legislation states that an offense does not require proof that the assailant had knowledge that the victim was pregnant. Hart noted that murder is a leading cause of death among pregnant women and in many cases the attack is made with the intention to kill the unborn child.

The House passed similar unborn victims bills in 1999 and 2001, but they never made it through the Senate, which could still kill this one despite a Republican majority that strongly favors it.

Rocha said she was disappointed that Democratic senators, including California's Barbara Boxer (search) and Dianne Feinstein (search), opposed the measure. She also called on Democratic candidates Sen. John Kerry and Sen. John Edwards to support the bill.

"Before politicians say that Conner was not really a victim of a crime, they need to think long and hard about whether they really want to say that," she said.

The legislation would apply only to attacks on women that qualify as federal offenses, such as terrorist attacks, bank robberies, drug trafficking and assaults on federal land.

Supporters said polling shows 80 percent of Americans support bringing two separate charges against the murderer of a pregnant woman who kills the unborn child.

"Ultimately, the criminal law is not a schedule of punishments. It is an expression of society's values. Anything less than the legislation before us today simply does not resonate with society's sense of justice." said Rep. James Sensenbrenner, R-Wis., chairman of the House Judiciary Committee.

Groups on both sides of the abortion issue have weighed in heavily on the bill.

The National Right to Life Committee (search) urged its supporters to lobby for the legislation and carried on its Web page a 2003 e-mail from Democratic presidential front-runner Kerry voicing opposition to a Senate version.

NARAL Pro-Choice America (search) said Congress must do more to protect pregnant women from violence but said the unborn victims bill was a "deceptive attempt to erode Roe v. Wade," the Supreme Court decision affirming a woman's right to end a pregnancy.

Fox News' Major Garrett and The Associated Press contributed to this report.