In an argument that lasted almost two hours, all six conservative justices indicated they would let states start banning abortion far earlier than the court’s precedents have previously allowed. Under a 1992 ruling, states can’t impose significant obstacles before fetal viability, which the court suggested was around 23 or 24 weeks at the time. 

“If it really is an issue about choice, why is 15 weeks not enough time?” Chief Justice John Roberts asked the lawyer challenging the Mississippi law on behalf of the state’s lone abortion clinic.

Two other pivotal justices, Brett Kavanaugh and Amy Coney Barrett, suggested they might go further and overturn the landmark Roe v. Wade ruling, which legalized abortion nationwide in 1973. Kavanaugh listed a series of famous cases, including decisions that outlawed school segregation and legalized gay marriage, in which the court overturned precedents.

“If we think that the prior precedents are seriously wrong—if that—why then doesn’t the history of this court’s practice with respect to those cases tell us that the right answer is actually a return to the position of neutrality and not stick with those precedents in the same way that all those others didn’t?” Kavanaugh asked.

Barrett questioned the contention by abortion-rights advocates that women would be forced into bearing the burden of parenthood if they couldn’t terminate a pregnancy. She said all 50 states have “safe haven” laws that let women relinquish their parental rights and put a baby up for adoption after giving birth. 

“Why don’t the safe haven laws take care of that problem?” Barrett asked.

Even if the court doesn’t explicitly overturn Roe, a decision upholding Mississippi’s law would have a far-reaching impact. It would give states new license to curb abortion access, guaranteeing tighter restrictions in much of the country.

—With assistance from David Yaffe-Bellany.