Lawmakers in the US state of Iowa, hoping for a decisive court battle over a flashpoint social issue, moved Wednesday to ban abortions when a foetal heartbeat is detected -- as early as six weeks into a pregnancy.
The ban approved by the Midwestern state's Republican-controlled legislature is considered the most restrictive in the country. Critics say it would deny abortions to many women before they even know they are pregnant -- with an exception for victims of rape or incest.
The state's Republican governor Kim Reynolds, an abortion opponent, has remained silent about whether she will sign the bill into law.
But other abortion foes celebrated, hailing the legislation as the first step in potentially dismantling Roe v. Wade -- the landmark 1973 Supreme Court decision that granted women the legal right to an abortion.
That right remains tenuous as debate rages across the country over the issue, especially in areas where conservatives are in power and hope to push the issue for reconsideration by the high court.
Abortion opponents hope Republican President Donald Trump soon will have an opportunity to appoint at least one more conservative justice -- thus tilting the high court's ideological balance in their favour.
Supreme Court Justice Ruth Bader Ginsberg, seen as a liberal, is 85 years old, while Justice Anthony Kennedy, a moderate, is 81.
Congressman Steve King of Iowa, a conservative Republican who sits on the powerful judiciary committee in the US House of Representatives, praised Iowa's so-called "heartbeat" ban, describing it as "the most consequential legislation in Iowa history" that could "set the stage" to challenge abortion nationally.
"We have a pro-life House of Representatives, a pro-life United States Senate, a pro-life president, and a United States Supreme Court that may well be receiving a new Constitutionalist Justice in the near future," he said in a statement.
Many Iowa legislators expected the "heartbeat" abortion ban to trigger a lawsuit, and they will have an uphill battle to defend it.
The Supreme Court in 2016 rejected appeals by both North Dakota and Arkansas to preserve similar "heartbeat" laws, which had been struck down by lower courts.
The American Civil Liberties Union quickly condemned the Iowa bill's passage and vowed to defend abortion rights in the state.
"All we can say right now is that we fought this legislation every step of the way and regret that it has made it this far," ACLU of Iowa's spokeswoman Veronica Fowler told AFP.
"It is clearly unconstitutional and it effectively blocks the right (to) an abortion for most women," she said.
The battle in Iowa is the latest in a long list of recent efforts to curb abortion rights.
The Guttmacher Institute, a pro-abortion research group, has tallied 400 new abortion restrictions in states between 2011 and 2017.
Consequently, there have been numerous legal challenges.
Until Wednesday, the most restrictive abortion ban was in Mississippi. Enacted in March, the southern state outlawed the procedure after 15 weeks of pregnancy.
A judge halted the law while a lawsuit moves forward.
A similar fate befell Kentucky's new ban on second-trimester abortions. It was halted by a federal court in April.