The Supreme Court challenge to a Texas law that has dramatically reduced the number of abortion clinics in the state is the justices' most significant case on the hot-button issue in nearly a quarter-century.
One of this election-year term's biggest cases is being argued Wednesday before a court altered by the death of Justice Antonin Scalia.
The Texas law has been replicated across the South and elsewhere, part of a wave of state abortion restrictions in the past five years.
States mainly led by Republicans have tried to limit when in a pregnancy abortions may be performed, restricted abortion-inducing drugs that take the place of surgery, and increased standards for clinics and the doctors who work in them.
The Supreme Court case involves that last category. A Texas law enacted in 2013 requires doctors who perform abortions to have admitting privileges at nearby hospitals. It also prohibits clinics from providing abortions unless they meet the standards of outpatient or ambulatory surgical centers.
The high court has partially blocked those measures. If allowed to take full effect, all but 10 clinics in Texas would have to close. There would be no abortion providers in the state's rural areas or west of San Antonio. The only clinic in the Rio Grande Valley would be allowed to remain open on a limited basis. Before the law was passed, there were roughly 40 clinics in the state. About half have closed.
The case offers competing views of how to protect women's health. The clinics contend abortions are safer than many other medical procedures that are less stringently regulated and that the clinic regulations have only one purpose: to reduce the availability of abortions.
"These laws are tantamount to an outright ban for too many," said Amy Hagstrom Miller, chief executive of Whole Woman's Health, which operates clinics in Texas and other states.
Defenders of the laws in Texas and elsewhere argue that states have discretion to take steps to make abortions safer. Alabama and other states backing Texas told the Supreme Court that states were within their rights to apply health regulations to clinics for the sake of patients.
"Obviously I'm pro-life and I would like to limit the number of abortions, but here we were looking at women's health and safety," said Republican Gov. Robert Bentley of Alabama, a doctor who signed his state's admitting privileges law.
Texas Solicitor General Scott Keller, who will defend the law at the Supreme Court, said Texas acted in response to the high-profile case of Philadelphia abortion doctor Kermit Gosnell. He is serving a life sentence after his conviction for killing three babies born alive and for the overdose death of a woman who was a clinic patient.
A federal judge in Texas struck down parts of the law as not intended to promote women's health and clearly aimed at reducing access to abortion. But the 5th US Circuit Court of Appeals in New Orleans largely accepted the state's argument.
The justices' June 2015 order putting the appellate ruling on hold at least suggests that there is a majority to cut back on the regulations. The clinics and abortion-rights groups are hoping for a ruling that might bolster challenges to other restrictions on abortion.
To prevail, they still need Justice Anthony Kennedy's vote, along with the reasonably certain votes of four more liberal justices, just as they did before Justice Scalia's death. Justice Kennedy was part of the 5-4 majority to reaffirm abortion rights in 1992, then wrote the court's decision in 2007 that upheld a federal law banning a certain procedure that opponents call partial-birth abortion. That was also a 5-4 split.
A broad high court ruling striking down the Texas provisions would show that the court's 1992 decision still "has some teeth in it," said Stephanie Toti, the lawyer who will argue the clinics' case.
Without Scalia, the best that supporters of these laws can hope for is a 4-4 tie, which would uphold the appeals court's endorsement of the Texas law and perhaps affect similar laws in Louisiana and Mississippi because they are part of the same judicial circuit as Texas.
A trial judge also struck down Louisiana's admitting privileges law, but the 5th Circuit has allowed Louisiana to enforce the law as the case makes its way through the courts.
Two of the state's four clinics have closed in response and a third will have to close soon, said Nancy Northup, president of the Center for Reproductive Rights. On Friday, the clinics said in an emergency appeal to the high court that only a New Orleans clinic would remain open if the state is allowed to enforce the law. They want the justices to block the ruling and let them stay open.
A split decision in the Texas case would have no effect on laws that have been blocked in Alabama and Oklahoma, among other states.
Women already make the drive from Louisiana and Mississippi to have abortions at the West Alabama Women's Center in Tuscaloosa, Alabama, said Dr. Willie Parker, who performs abortions in Alabama, Georgia and Mississippi. The Tuscaloosa clinic is Alabama's busiest. It would be among four clinics, out of five, that would have to close under the Alabama admitting privileges law, which is not in effect.
If the Texas law stands and others like it are enforced, Parker said, "it won't mean fewer unintended pregnancies. It won't mean fewer fatally flawed pregnancies. It will mean women will be left without a safe and legal means of ending pregnancy."
Ashley McGuire, a senior fellow with the anti-abortion group The Catholic Association, said the fight to limit abortions will continue no matter what the Supreme Court says. "This fight is not going away anytime soon," Ms. McGuire said.