The Iowa state legislature passed a bill on Wednesday outlawing abortions performed after fetal pole cardiac activity can first be detected, which is around six weeks of pregnancy with a transvaginal ultrasound. If signed by Gov. Kim Reynolds, a Republican who has said abortion is “equivalent to murder,” the bill will become the country’s strictest limit on abortion rights.

“Today we are taking a courageous step to tell the nation that Iowa will defend its most vulnerable: those without a voice, our unborn children,” said state Rep. Shannon Lundgren in the Iowa House during discussion of the bill.

In Roe v. Wade and Planned Parenthood v. Casey, the Supreme Court has affirmed the right to abortion care until fetal viability, around 24 weeks’ gestation. The Iowa bill would make abortion illegal as soon as what anti-abortion advocates call a “heartbeat”—a loaded, inaccurate term—can be detected, before many women even know they’re pregnant. When North Dakota passed a similar law in 2013, a federal judge blocked it, calling the legislation “clearly unconstitutional.” Arkansas passed its own “heartbeat” bill in 2013, too, though it only banned abortions performed 12 weeks or more after a woman’s last period, when a “heartbeat” could be detected by an abdominal ultrasound. Two federal courts stopped that law from going into effect, ruling that no fetus has ever been proved viable at 12 weeks’ gestation.

The most restrictive gestation-based abortion laws currently in effect in the U.S. are the 20-week abortion bans on the books in 19 states. Mississippi passed a 15-week ban in March, but a judge issued a temporary injunction just one day after the governor signed it, preventing the law from taking effect before it’s argued in court.

Reynolds told the Des Moines Register that she’s waiting to see the bill before deciding whether or not to sign it into law, but her spokeswoman told the New York Times that she remains “100 percent pro-life and will never stop fighting for the unborn.” The bill makes some exceptions for fetal abnormalities “incompatible with life,” threats to the life of the pregnant woman, and survivors of rape and incest who report the crimes perpetrated against them within 45 and 140 days, respectively.

Republicans hope the Supreme Court, strengthened by Neil Gorsuch and any other justices Trump nominates during his term, will agree to evaluate this law and roll back the rights to abortion and privacy affirmed by previous decisions. “It is time for the Supreme Court to weigh in on the issue of life,” Lundgren said this week. “It has taken decades for the science to catch up to what many have believed all along: that she’s a baby.”

The willingness of mainstream Republicans to support extreme anti-abortion legislation is a notable shift in a party that has spent a lot of energy eroding reproductive rights with incremental legislation, including mandatory waiting periods and excessive building-code requirements for abortion clinics. In Texas and elsewhere, anti-abortion groups are fighting over how radical their movement should be. Some would rather their states not waste millions of dollars defending laws that are patently unconstitutional. Others believe it’s their duty to push for the most restrictive abortion bans that could possibly pass their state’s legislature.

The recent passage of Mississippi’s 15-week ban and this new Iowa bill suggest that Republicans are getting more bullish about their chances in court. Recently, in a dissent on a 7th U.S. Circuit Court of Appeals decision striking down Indiana laws that banned abortions sought for reason of fetal sex or disability, Judge Daniel Manion wrote that abortion has become a “super-right…more ironclad even than the rights enumerated in the Bill of Rights” in U.S. law. He also urged the Supreme Court to overturn Roe v. Wade. Manion was appointed by Ronald Reagan, but Trump is currently packing the federal judiciary with far-right ideologues just as conservative as Manion.

When Mike Pence says the U.S. will end legal abortion “in our time,” when anti-abortion activists at the March for Life say it might be “the last march we have to have” because Trump is in office, this is what they’re referring to: a plan to shift the makeup of the judiciary for an entire generation, in the hopes of, among other things, allowing states to make abortion a crime. As recently as 2016, the Supreme Court wasn’t interested in reconsidering Roe; that year, the justices declined to grant certiorari to defenders of Arkansas’ 12-week “heartbeat” ban, effectively striking the law for good. With Gorsuch now on the bench and a few left-leaning justices getting up there in age, the hope is that a similar petition from Iowa could, in the near future, yield a very different decision.