The Supreme Court hears one of its most important oral arguments of the current term on Wednesday, and much more is at stake than policy on the perennially divisive issue — abortion rights — at the heart of the litigation. The court’s integrity itself will be on trial. All Americans, and certainly all nine justices, should favor a ruling consistent with precedent — and the vital principle that constitutional rights do not vary according to which party gets to nominate members of the court.

In 2016, the Supreme Court struck down a Texas law that required doctors who perform abortions at outpatient clinics to have “active admitting privileges” at a hospital no more than 30 miles away. The unstated but clearly intended effect of the statute was to impose a condition clinics could not meet, thereby shutting them down. By a vote of 5 to 3, the justices ruled that the law’s ostensible medical rationale was hollow and that it created an “undue burden” on women’s right to choose an abortion, contrary to precedent.

Nevertheless, in January 2019 the New Orleans-based U.S. Court of Appeals for the 5th Circuit, dominated by Republican appointees, finalized a ruling upholding a Louisiana law nearly identical to the recently rejected Texas one. The 5th Circuit justified its defiance of the Supreme Court by noting operational differences between the two states’ medical systems; but the main difference between 2016 and 2018 was the election of Donald Trump as president and his empowerment to appoint justices who oppose Roe v. Wade.

Now you can see why the technical legal issues in the case, complex and weighty as they are, pale in comparison to the real question: whether the Supreme Court will reverse a freshly minted pro-choice precedent after the justice who cast a fifth and deciding vote for it in 2016, Anthony M. Kennedy, retired in 2018 — and Brett M. Kavanaugh replaced him. The good news, so far, is that the chief justice, John G. Roberts Jr., has acted as if what matters most is the rule of law. In February 2019 he joined the court’s more liberal justices to block implementation of the 5th Circuit decision pending the decision of the cases that will be argued March 4.

There is some question as to how Chief Justice Roberts and Justice Kavanaugh, who dissented from the chief justice’s stay order a year ago, may rule now — when faced with the temptation to deal a body blow to Roe v. Wade, as the party that elevated them to the bench so fervently wishes. The correct response is clear, however, as the chief justice implied by voting for the stay and as two of his colleagues would also agree if the words of their dissenting opinions from the court’s 2016 ruling against Texas mean anything. “Unless the Court abides by one set of rules to adjudicate constitutional rights, it will continue reducing constitutional law to policy-driven value judgments until the last shreds of its legitimacy disappear,” Justice Clarence Thomas wrote. To which Justice Samuel A. Alito Jr. added: a “patent refusal to apply well-established law in a neutral way is indefensible and will undermine public confidence in the Court as a fair and neutral arbiter.”

Read more: