WASHINGTON (BP) -- The Arkansas legislature has overridden a veto to enact the earliest ban on abortion in the United States.

The state House of Representatives voted 56-33 Wednesday (March 6) to override Gov. Mike Beebe's veto, thereby providing final approval to a measure that bans abortion of unborn babies whose heartbeat has been detected by ultrasound at 12 weeks or later. The Senate had voted 20-14 the day before for the veto override, which requires only a majority in Arkansas.

The law marks a new front in the effort by states to regulate abortion, and it remains to be seen if it will survive a challenge in court.

Before Arkansas' heartbeat law, a ban at 18 to 20 weeks after fertilization had been the earliest enacted by a state. A federal judge in Idaho struck down that state's 20-week prohibition -- which is based on evidence a baby in the womb experiences pain by that point -- on the same day Arkansas enacted its 12-week ban.

The Arkansas legislature, in fact, had enacted a 20-week ban by a veto override a week before its latest override. Beebe, a Democrat, vetoed the 20-week ban Feb. 26, and the House and Senate quickly followed with successful override votes.

The ACLU of Arkansas quickly promised a lawsuit asking a federal court to strike down the heartbeat ban.

When Beebe vetoed the Arkansas Human Heartbeat Protection Act, he said he did so because the bill "blatantly contradicts the United States Constitution, as interpreted by the Supreme Court." He also expressed concern a legal challenge would be costly to taxpayers.

Rep. Ann Clemmer, the bill's Republican sponsor in the House, disagreed with the governor's assessment.

"We believe that because we put it at 12 weeks it will survive a court challenge -- we are setting it at the end of the first trimester," Clemmer said, according to The Washington Times.

The state's fetal-homicide law "declares a 12-week-old baby in utero to be a person and we have prosecuted individuals who have hurt babies in utero," she said.

The difference between the way the Arkansas law defines viability for an unborn child and the way the Supreme Court has defined it could prove a problem for the ban in court. The high court has ruled a state can restrict abortion after viability, which is typically considered to be at about 22 to 24 weeks after fertilization. Arkansas' heartbeat ban defines viability as "a medical condition that begins with a detectible heartbeat."

Some pro-life advocates say a ban at 12 weeks is a strategic mistake because of the Supreme Court's past rulings and current make-up, which favors the pro-choice side.

"As much as we would like to protect the unborn at that point, it is futile and it won't save any babies," said James Bopp, the National Right to Life Committee's general counsel, according to The New York Times.

Bopp -- a longtime pro-life, legal advocate -- predicted lower federal courts will strike down the law and the Supreme Court probably will not accept the case.

The heartbeat ban requires a doctor to perform an abdominal ultrasound on the mother to determine if her unborn child has a heartbeat that can be detected. The law has exceptions for rape, incest, a threat to the life of the mother, a serious risk of a major impairment of the mother's health and a "highly lethal fetal disorder."

The law will go into effect 90 days after the close of Arkansas' legislative session.

Roe v. Wade and Doe v. Bolton -- companion rulings by the U.S. Supreme Court in 1973 -- legalized abortion for effectively any reason throughout pregnancy. Later high court opinions, especially in a 1992 case, upheld some state restrictions on abortion, and states have passed a variety of successful regulations since those rulings.

Tom Strode is Washington bureau chief for Baptist Press. Get Baptist Press headlines and breaking news on Twitter (@BaptistPress), Facebook (Facebook.com/BaptistPress ) and in your email ( baptistpress.com/SubscribeBP.asp).

Copyright (c) 2013 Southern Baptist Convention, Baptist Press www.BPNews.net