WASHINGTON -- Adding fuel to the already fierce debate over abortion, Republicans in Congress are invoking the Laci Peterson murder case as they try to enact the first federal law to endow a fetus with legal rights separate from the expectant mother.

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Laws similar to the federal bill already are on the books in more than half the states, and with Republicans in control of both chambers of Congress, the federal measure has a good chance of passing.

President Bush has pledged to sign the act, which sponsors have renamed "Laci and Conner's Law" in honor of Laci Peterson and her unborn son. Laci's husband, Scott Peterson, has been charged with double murder by prosecutors in California, which has a fetal homicide law.

"In the Peterson case, I've heard no one go on radio or TV and say there shouldn't be an indictment for the death of that child," said Sen. Mike DeWine (news, bio, voting record), R-Ohio, the act's chief Senate sponsor. "The fact is there are two victims — it's a fiction to say there aren't."

Abortion-rights activists counter the gruesome murder case is being exploited callously as part of a broad strategy to undermine the Supreme Court's 1973 Roe v. Wade decision legalizing abortion.

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Read literally, the pending Unborn Victims of Violence Act is not an anti-abortion measure. It explicitly exempts abortion while making murder or injury of an unborn child a separate offense during the commission of certain existing federal crimes.

Abortion-rights groups nonetheless are alarmed that Congress might, for the first time, recognize a fetus as a potential victim independent of the expectant mother.

"This is one of their strategies — to ascribe legal rights to the fetus separate from the woman," said Kate Michelman, president of NARAL Pro-Choice America. "Their intent is to do whatever they can to contribute to the ultimate goal of overturning Roe v. Wade and taking away a woman's right to control her reproductive life."

Twice since 1999, the Unborn Victims act cleared the U.S. House of Representatives but failed to reach the Senate floor in the face of opposition from abortion-rights supporters.

The latest version of the bill has been endorsed by Laci Peterson's parents and siblings. In a letter to sponsors this month, they said the measure "is very close to our hearts."

Critics of the bill are upset that its sponsors so readily embraced the link to the high-profile murder case.

Renaming the bill for Laci and Conner "is shameless exploitation of a horrific tragedy," Michelman said. "It sickens me."

Abortion-rights supporters say violence against pregnant women can be combated without recognizing a fetus as a separate person. Rep. Zoe Lofgren, D-Calif., is proposing an alternative bill that would provide a possible life sentence for any assailant who terminates a pregnancy.

"We can protect women from violence without opening the Pandora's box of the abortion debate," Lofgren wrote to her House colleagues.

In an interview, Lofgren expressed dismay that crime victims like the Petersons are used as "the poster child for the right-wing agenda."

She also contended supporters of the Unborn Victims Act were disingenuous in downplaying its potential impact on abortion rights.

"I can deal with people who simply disagree on abortion," she said. "What bothers me are people who aren't honest about what they're doing."

The bill would not permit prosecution for any abortion to which a woman consented, or for any act by an expectant mother — even an illegal act such as drug abuse — that harmed her unborn child.

The bill also would not supersede comparable state laws, but would apply to various federal crimes, including kidnapping across state lines, drug-related drive-by shootings, and assaults occurring on federal property.

The measure has strong backing from many anti-abortion groups, including the prominent National Right to Life Committee. Its legislative director, Douglas Johnson, said the act deserves support regardless of its effect Roe v. Wade.

"Whoever killed Laci and Conner Peterson didn't perform an abortion," Johnson said. "It's important to protect unborn children from all threats."

Within the anti-abortion movement, some activists criticize the bill because it exempts legal abortions. But Dr. Joe Cook, vice president of the American Association of Pro Life Obstetricians and Gynecologists, said "we have to approach this in a way that's doable, a step at a time.

"This bill is aimed at establishing that a fetus in utero is a human being and has human rights."