A proposed bill being considered in South Dakota could redefine “justifiable homicide” to potentially include killings that are intended to prevent harm to a fetus. As crazy as this sounds, this law could provide a legal defense to a person who murders anyone assisting in an therapeutic abortion. When I first read the initial reporting, I thought it had to a story in the Onion or some loony politician following through on a wacky campaign promise. However, this proposed law actually made it through committee on a 9-3 party line vote in a Republican dominated legislature. This is the same South Dakota Legislature that earlier this week attempted to criminalize surrogacy but, in a moment of apparently rare lucid thinking, dropped the bill.

While there is no way a bill like this would survive a constitutional challenge, it nevertheless provides some scary insight into the minds of some South Dakotans:

A law under consideration in South Dakota would expand the definition of “justifiable homicide” to include killings that are intended to prevent harm to a fetus—a move that could make it legal to kill doctors who perform abortions. The Republican-backed legislation, House Bill 1171, has passed out of committee on a nine-to-three party-line vote, and is expected to face a floor vote in the state’s GOP-dominated House of Representatives soon.

The bill, sponsored by state Rep. Phil Jensen, a committed foe of abortion rights, alters the state’s legal definition of justifiable homicide by adding language stating that a homicide is permissible if committed by a person “while resisting an attempt to harm” that person’s unborn child or the unborn child of that person’s spouse, partner, parent, or child. If the bill passes, it could in theory allow a woman’s father, mother, son, daughter, or husband to kill anyone who tried to provide that woman an abortion—even if she wanted one.

Jensen did not return calls to his home or his office requesting comment on the bill, which is cosponsored by 22 other state representatives and four state senators. UPDATE: Jensen spoke to Mother Jones on Tuesday morning, after this story was published. He says that he disagrees with this interpretation of the bill. “This simply is to bring consistency to South Dakota statute as it relates to justifiable homicide,” said Jensen in an interview, repeating an argument he made in the committee hearing on the bill last week. “If you look at the code, these codes are dealing with illegal acts. Now, abortion is a legal act. So this has got nothing to do with abortion.” Jensen also aggressively defended the bill in an interview with the Washington Post’s Greg Sargent on Tuesday morning.

“The bill in South Dakota is an invitation to murder abortion providers,” says Vicki Saporta, the president of the National Abortion Federation, the professional association of abortion providers. Since 1993, eight doctors have been assassinated at the hands of anti-abortion extremists, and another 17 have been the victims of murder attempts. Some of the perpetrators of those crimes have tried to use the justifiable homicide defense at their trials. “This is not an abstract bill,” Saporta says. The measure could have major implications if a “misguided extremist invokes this ‘self-defense’ statute to justify the murder of a doctor, nurse or volunteer,” the South Dakota Campaign for Healthy Families warned in a message to supporters last week.

The original version of the bill did not include the language regarding the “unborn child”; it was pitched as a simple clarification of South Dakota’s justifiable homicide law. Last week, however, the bill was “hoghoused”—a term used in South Dakota for heavily amending legislation in committee—in a little-noticed hearing. A parade of right-wing groups—the Family Heritage Alliance, Concerned Women for America, the South Dakota branch of Phyllis Schlafly’s Eagle Forum, and a political action committee called Family Matters in South Dakota—all testified in favor of the amended version of the law.

Jensen, the bill’s sponsor, has said that he simply intends to bring “consistency” to South Dakota’s criminal code, which already allows prosecutors to charge people with manslaughter or murder for crimes that result in the death of fetuses. But there’s a difference between counting the murder of a pregnant woman as two crimes—which is permissible under law in many states—and making the protection of a fetus an affirmative defense against a murder charge.

“They always intended this to be a fetal personhood bill, they just tried to cloak it as a self-defense bill,” says Kristin Aschenbrenner, a lobbyist for South Dakota Advocacy Network for Women. “They’re still trying to cloak it, but they amended it right away, making their intent clear.” The major change to the legislation also caught abortion rights advocates off guard. “None of us really felt like we were prepared,” she says.

Sara Rosenbaum, a law professor at George Washington University who frequently testifies before Congress about abortion legislation, says the bill is legally dubious. “It takes my breath away,” she says in an email to Mother Jones. “Constitutionally, a state cannot make it a crime to perform a constitutionally lawful act.”