The Supreme Court this week agreed to hear a direct challenge to the constitutional rule that states may not prohibit abortion before fetal viability, setting up a case over Mississippi’s ban on most abortions after 15 weeks of pregnancy and placing one of the nation’s most durable legal and political conflicts before a newly constituted Court.

The justices on Monday granted review in Dobbs v. Jackson Women’s Health Organization, limiting the case to a single question: whether all pre-viability prohibitions on elective abortions are unconstitutional. That framing is unusually consequential because the 15-week cutoff comes well before the point at which a fetus can survive outside the womb under current medical practice. Lower federal courts blocked the Mississippi law on that basis.

The case arrives at a Court that has changed substantially since its last major abortion ruling. Justice Amy Coney Barrett joined the Court last fall after the death of Justice Ruth Bader Ginsburg, giving Republican-appointed justices a 6-3 majority. The grant does not determine the outcome, but it ensures that the Court will directly confront the viability line that has structured abortion law for decades.

Mississippi asks the Court to reconsider the line

Mississippi enacted the Gestational Age Act in 2018. The statute bars most abortions after 15 weeks, with exceptions for medical emergencies and severe fetal abnormalities. The state’s petition asks the justices to permit greater state authority to restrict abortions before viability and argues that the Court’s existing framework has proved difficult to administer.

Jackson Women’s Health Organization, the state’s only licensed abortion clinic, sued almost immediately after the law was signed. In its brief opposing review, the clinic argued that the dispute was straightforward under existing precedent: a state cannot ban abortion before viability, and Mississippi did not contend that a fetus is viable at 15 weeks.

The U.S. Court of Appeals for the Fifth Circuit reached the same conclusion. Its 2019 decision said the statute prohibited abortions before viability and therefore could not be reconciled with controlling Supreme Court decisions. The appeals court stressed that lower courts are bound by the Supreme Court’s existing framework even when judges disagree with its reasoning or consequences.

Nearly five decades of precedent converge on viability

The modern constitutional framework begins with Roe v. Wade, the 1973 decision recognizing a constitutional right to terminate a pregnancy. The Court later revised Roe’s trimester framework but retained its central protection in Planned Parenthood v. Casey in 1992. Casey said states could regulate abortion before viability so long as they did not impose an undue burden, but they could not prohibit a woman from making the ultimate decision to terminate a pregnancy before viability.

That distinction has remained central even as the Court has allowed significant abortion regulation. In 2016, Whole Woman’s Health v. Hellerstedt struck down Texas requirements for abortion providers after examining the burdens imposed relative to the asserted medical benefits. And last year, in June Medical Services v. Russo, the Court invalidated a Louisiana admitting-privileges law that closely resembled the Texas provision.

Mississippi’s case is different in a critical respect. Rather than asking whether a regulation creates an undue burden, it presents a prohibition tied to a specific gestational age. If the Court concludes that a 15-week ban can stand despite the viability rule, states would have substantially more room to impose earlier limits.

The question the Court chose matters

Mississippi originally presented several questions, including challenges to the legal standing of abortion providers to sue on behalf of patients. The justices accepted only the first question concerning pre-viability prohibitions. That choice narrows the case while simultaneously making it more direct: the Court will consider the constitutional boundary itself rather than resolving the dispute on a procedural ground.

The Court’s composition makes that decision especially closely watched. Chief Justice John Roberts joined the judgment striking down Louisiana’s law in June Medical, relying on precedent even though he had dissented in the Texas case four years earlier. But the replacement of Ginsburg with Barrett has changed the arithmetic. A majority could now be assembled without Roberts if the five other Republican-appointed justices agree.

For Mississippi, the case is an opportunity to argue that states should be allowed to protect fetal life earlier in pregnancy and that viability is not a constitutionally required line. For the clinic and abortion-rights advocates, the dispute is about the stability of a rule that has defined the scope of state power for nearly half a century.

A decision could reshape state law nationwide

The practical stakes extend well beyond Mississippi. Numerous states have enacted or considered abortion restrictions designed to test the limits of Supreme Court precedent. Courts have generally blocked pre-viability bans when challenged, precisely because Roe and Casey reserve the ultimate decision to the pregnant woman before viability.

If the justices uphold Mississippi’s law, legislatures could move rapidly to adopt similar or earlier gestational limits. If the Court strikes it down, the viability rule would survive another direct challenge despite the Court’s ideological shift. Either way, the decision will provide the clearest indication yet of how the current Court intends to treat Roe and Casey.

The case will be argued during the Court’s next term, which begins in October. A decision would normally be expected by the end of that term. Until then, Mississippi’s 15-week ban remains blocked, and the legal status quo remains in place.

Monday’s grant therefore changes no abortion law immediately. What it changes is the question before the country. After years in which abortion cases often turned on clinic regulations, medical requirements, or procedural disputes, the Supreme Court has agreed to address the line itself: whether the Constitution continues to prevent states from banning abortion before viability.