Concluding her Senate floor speech in behalf of Judge Brett Kavanaugh—her vote for him was the decisive one—Republican Susan Collins expressed “her fervent hope” that he “will work to lessen the divisions in the Supreme Court so that we have fewer 5-4 decisions and so that public confidence in our judiciary and our highest court is restored.”

This is a lot to ask of Kava­naugh, and while there might be fewer 5-4 decisions thanks to his efforts, the far more important question about his service will concern the fate of a single case, Roe v. Wade (1973), in which the Court created a constitutional right to abortion extending through all nine months of pregnancy. About no other right did Collins say, “protecting this right is important to me.”

Roe was a 7-2 decision, the Court’s opinion written by Justice Harry Blackmun. The majority said that fetuses are not “persons in the whole sense.” Of course, if the majority had recognized that they are persons, period, they would have been persons with rights—including the right to life—that government is obliged to protect. Using dubious doctrine from the 1965 case of Griswold v. Connecticut, the majority instead created a right to abortion that was effectively absolute.

Roe did not immediately arouse organized opposition, but by the early 1970s the sides that have done battle ever since were solidifying. Together with the Dred Scott decision of 1857, which effectively created a constitutional right to slavery and pushed the country to civil war, Roe v. Wade stands as the most divisive of the Court’s rulings. It has been divisive in every way—legally, politically, and socially. And morally, too: Roe makes possible a culture of prenatal death in which more than 60 million lives have been taken.

Abortion cases have been on the Court’s docket since the 1980s. Narrow majorities have upheld some regulations of the abortion right. In Planned Parenthood v. Casey (1992) the Court reviewed regulations of that right from Pennsylvania. It was reported at the time that at least six justices disagreed with Roe. But the case was not overruled, notwithstanding its serious defects—including its lack of support in constitutional text and history, and the fact it took from the people their right to decide abortion policy. Roe nullified the disparate abortion laws of 46 states.

In her floor speech Senator Collins did not concern herself with that aspect of Roe, but instead discussed Kava­naugh’s views of Griswold, which voided a state law banning the use and sale of contraceptives. The Court relied then on the right of privacy that eight years later, in Roe, it would expand to include the abortion right. No nominee of a Republican president has dared to challenge Griswold since Robert Bork did in 1987, as a failed Reagan nominee. It is therefore understandable that Kava­naugh stayed far away from any fight over the case. Collins said Kava­naugh had told her when they spoke before the hearings that Griswold was “settled law,” the correct application of cases from the 1920s. And she reminded her national audience that in his testimony Kava­naugh “noted repeatedly that Roe had been upheld by . . . Casey, describing it as ‘precedent on precedent.’ ”

Precedent is a judicial decision, and adhering to precedent is also known as letting the decision stand (stare decisis, in Latin). A decision that is allowed to stand may govern the resolution of similar issues in future cases. Adherence to precedent, Kava­naugh told Collins, can provide stability, predictability, reliance, and fairness. But not all decisions are good ones, and overruling a decision may sometimes be called for. Collins pointed to Plessy v. Ferguson (1896), which legalized segregation and was overturned, of course, by Brown v. Board of Education (1954). Kava­naugh agreed with that overruling, describing it to Collins as the correction of a “grievously wrong” decision that had upheld racial inequality.

Kava­naugh is hardly an authority on the doctrine of precedent. He has written little on the subject and as a federal appeals court judge he had no experience in applying it, fully complying with the Supreme Court’s demand that lower court judges not overrule its precedents. But Kava­naugh is a quick study, and he impressed Collins in their conversations about precedent. She thinks that someone who believes precedent is rooted in the Constitution “would follow long-established precedent except in those rare circumstances where a decision is grievously wrong or ‘deeply inconsistent with the law,’ ” another Kava­naugh phrase.

Clearly, the senator regards Kava­naugh that way. As Collins explained, Kava­naugh sees precedent as not merely a policy or practice or tradition but as part of the judicial power located in Article III. He’s the first Supreme Court nominee to find precedent in the Constitution, she said, but his reading doesn’t appear to be an activist one: In Reconciling Originalism and Precedent, legal scholars John McGinnis and Michael Rappaport write, “The Constitution as a matter of judicial power incorporates a minimal notion of precedent.” Moreover, they say, “the Constitution treats precedent as a matter of federal common law that is revisable by congressional statute.”

Like previous confirmation struggles, the Kava­naugh fight ultimately concerned the abortion-rights precedents and their prospects in a newly composed Supreme Court. Roe v. Wade and Planned Parenthood v. Casey are certainly “long-established,” but so was Plessy. Roe and Casey were likewise “grievously wrong” and “deeply inconsistent” with the law, arguably even more so than Plessy. In their conversations Collins asked Kava­naugh whether it would be sufficient to overturn a long-established precedent if five current justices believed it was wrongly decided. His answer: “No.” Apparently, as Kavanaugh sees the matter, at least six would be needed to overrule Roe and Casey. And that would require the replacement of a liberal justice with a conservative who believes that Roe and Casey were wrongly decided, with the new appointment effected by a Republican president and a Republican Senate. It could be a long time coming.