Today, on the 48th anniversary of the landmark 1973 ruling Roe v. Wade, the U.S. Supreme Court is scheduled to decide whether or not to hear a Mississippi abortion case that could ultimately challenge Roe.

The case, Dobbs v. Jackson Women’s Health Organization, involves a 2018 Mississippi law that banned all abortions after 15 weeks of pregnancy. The law allowed for abortions in medical emergencies or in cases of a severe fetal abnormality, but didn’t include exceptions for rape or incest.

The law was only in effect for a few hours before it was halted by a legal challenge from Mississippi’s only abortion clinic, Jackson Women’s Health Organization.

Under Roe v. Wade, states are not permitted to ban abortion before the fetus would be viable to live outside the womb. And in the 1992 Supreme Court case Planned Parenthood v. Casey,  justices clarified that states have the right to implement restrictions on abortion after the point of viability. At the time of Roe, viability was considered to be after 24 weeks. But the Supreme Court has never specified what the point of viability is, which conservatives argue is a reason to bring up a case like the Mississippi ban.

Mississippi Attorney General Lynn Fitch requested the Supreme Court consider Dobbs v. Jackson Women’s Health Organization last June in order to rule on whether banning abortions before the pre-viability mark was unconstitutional. The request also asked the court to reevaluate its rulings on Planned Parenthood v. Casey–which said abortion restrictions prior to the point of viability would be unconstitutional if they placed an “undue burden” on the woman—and the similar Whole Woman’s Health v. Hellerstedt case. That ruling held that requiring abortionists to have admitting privileges at a nearby hospital and requiring abortion clinics to have facilities comparable to ambulatory surgical centers placed an undue burden on abortion access.

“This court’s jurisprudence points in different directions when it comes to states’ ability to regulate pre-viability abortions,” Fitch argued in the petition. The viability line is an arbitrary line that ignores states’ interests pre-viability and finds no basis in the Constitution.”

In October, Fitch filed a supplemental brief offering additional arguments based on references to a recent decision of the court regarding hospital admitting privileges in Louisiana.

John Bursch, Alliance Defending Freedom’s vice president of appellate advocacy and senior counsel, agrees that the Supreme Court’s lack of specificity when defining viability is problematic:

“Various justices and concurring or dissenting opinions over the years have been highly critical of the viability line as the test for when abortion restrictions can take place because it’s artificial and constantly changing based on science.”

“We are hopeful that the court will accept our case and allow Mississippi to defend innocent life as the legislature and the people of this great state intend,” Fitch said.

But if the justices ultimately decline to take Dobbs v. Jackson Women’s Health Organization, the Supreme Court will likely have another opportunity to weigh in on abortion, as more than a dozen abortion cases are circulating in the lower courts.