FARGO, N.D. — Governor Jack Dalrymple of North Dakota approved the nation’s toughest abortion restrictions on Tuesday, signing into law a measure that would ban nearly all abortions and inviting a legal showdown over just how much states can limit access to the procedure.
Dalrymple, a Republican, signed three bills passed by the Republican-controlled Legislature in Bismarck.
The most far-reaching law forbids abortion once a fetal heartbeat is ‘‘detectable,’’ which can be as early as six weeks into a pregnancy. Fetal heartbeats are detectable at that stage of pregnancy using a transvaginal ultrasound.
Most legal scholars have said the law would violate the Supreme Court’s finding in Roe v. Wade that abortions were permitted until the fetus was viable outside the womb, generally around 24 weeks. Even some leaders of the antiabortion movement nationally have predicted that laws banning abortion so early in pregnancy are virtually certain to be declared unconstitutional by federal courts.
“Although the likelihood of this measure surviving a court challenge remains in question, this bill is nevertheless a legitimate attempt by a state legislature to discover the boundaries of Roe v. Wade,’’ Dalrymple said in a statement.
The Supreme Court, he added, ‘‘has never considered this precise restriction’’ in the heartbeat bill.
‘‘I think there’s a lot of frustration in the prolife movement,’’ said Paul B. Linton, a constitutional lawyer in Illinois who was formerly general counsel of Americans United for Life. ‘‘Forty years after Roe v. Wade was decided, it’s still the law of the land.’’
Abortion-rights advocates who had gathered here to urge the governor to veto the bills quickly condemned his decision as effectively banning abortion in the state and as an attack on women. Without judicial intervention, the three bills are scheduled to take effect Aug. 1.
‘‘In the past it’s been, ‘We’re going to try and make it more difficult, more hoops, more obstacles for women to have to jump through or jump over,’ ’’ said Tammi Kromenaker, the director of Red River Women’s Clinic in Fargo, the state’s only abortion provider. ‘‘But this is specifically: ‘Let’s ban abortion. Let’s do it. Let’s challenge Roe v. Wade. Let’s end abortion in North Dakota.’ ’’
The Center for Reproductive Rights, in New York, immediately condemned the new laws and said it would file a challenge to the fetal heartbeat ban.
The larger, established opponents of abortion including the National Right to Life, Americans United for Life, and the Roman Catholic Church have not supported fetal heartbeat proposals, saying that until the court’s composition changes, they could be counterproductive.
These groups have instead pursued more incremental measures, like waiting periods, requiring sonograms and imposing stricter regulations on doctors and clinics and, in 10 states so far, bans on abortion at 20 weeks, an approach that is nearer to the viability threshold, but is under challenge in the courts.
‘‘There are two clashing forces in the antiabortion movement now,’’ said Caitlin Borgmann, a law professor and abortion-rights advocate at City University of New York. ‘‘The incrementalists are chipping away at Roe and the others are getting impatient.’’
With passage of heartbeat laws in Arkansas and North Dakota, ‘‘this extreme wing of the movement has definitely gained momentum,’’ Borgmann said. ‘‘But it can only go so far because they can’t win in the courts.’’
Abortion-rights advocates here have felt particularly on the defensive this year because of the sheer number of bills introduced and their sweeping scope.
Previously approved abortion measures requiring the state’s lone provider to do things like post new signs, fill out more paperwork, distribute literature and offer ultrasounds were seen as burdensome but manageable.
Some say that North Dakota lawmakers and activists opposed to abortion aggressively pushed their cause this year because they were emboldened by the huge cash reserves from oil revenue that the state can use to fight legal challenges to its laws, and by the successful passage of abortion restrictions elsewhere in the country.