In the spring, June Medical Services v. Gee will be the first abortion rights case heard by the conservative-majority U.S. Supreme Court. It’s hard to overstate how much is at risk.

The case challenges the strength of Whole Woman’s Health v. Hellerstedt, the 2016 Supreme Court victory that struck as unconstitutional a Texas law identical to the one at issue in June Medical Services. That is a big deal. June Medical Services also has the potential to limit the ability of abortion providers to challenge certain anti-choice restrictions on behalf of their patients. That is also a big deal. And if those stakes weren’t quite high enough, if the Roberts Court sides with Louisiana, it will mark the beginning of a fundamental reordering of abortion rights jurisprudence that could call into question the very rule of law.

The question the Supreme Court will decide should be quite simple, as far as Supreme Court questions go. Did the U.S. Court of Appeals for the Fifth Circuit get it wrong when it upheld Louisiana’s Act 620, a law that requires abortion providers to maintain hospital admitting privileges? The answer should be just as simple, given that Act 620 is identical to a provision the Court declared unconstitutional in Whole Woman’s Health: Yes. But when it comes to the Roberts Court and abortion rights, nothing is simple.

Anti-choice advocates have been trying to enforce Act 620 for five years, to no avail. A district court temporarily blocked the law in 2014 and again in 2016. In April 2017, that court permanently blocked Act 620, ruling that it was unconstitutional and an undue burden on the constitutional right to an abortion in violation of principles the Supreme Court set forth in Planned Parenthood v. Casey and clarified in Whole Woman’s Health. The district court further found that the severe burdens imposed by the law would fall most heavily on low-income people and people of color. That didn’t matter to the conservative Fifth Circuit Court of Appeals, whose justices ruled Act 620 could take effect. In the Fifth Circuit’s estimation, there just wasn’t enough proof clinics would close and abortion rights would be unduly burdened under the law—despite a six-day trial and mountains of evidence to the contrary.

The ruling was, as my colleague Imani Gandy rightly described it at the time, absurd. And if it’s allowed to stand, Louisiana would only have a single abortion provider—and other states would undoubtedly follow suit.

Attorneys challenging the restrictions on behalf of abortion providers petitioned the Supreme Court to summarily reverse the Fifth Circuit, a mechanism where the Court takes the case and overturns the appellate court decision. Instead of doing so, the Court decided to take the case and hear Louisiana’s arguments that the Court should limit the reach of Whole Woman’s Health to effectively only the state of Texas. Louisiana also wants the Court to upend nearly 50 years of abortion rights jurisprudence and rule that providers cannot sue to challenge abortion restrictions on behalf of their patients if those restrictions are passed to benefit the so-called health and safety of the patient.

The fact that the Roberts Court is even willing to entertain Louisiana’s arguments in this case shows just how endangered abortion rights are with the Court’s new conservative majority. That fact is not lost on the advocates flooding the Court with friend-of-the-court briefs urging the justices to reject Louisiana’s arguments and keep Whole Woman’s Health intact.

“Louisiana can defend Act 620 only by misrepresenting the realities of abortion care and by challenging decades of precedent recognizing doctors’ standing to assert the rights of their patients,” one wrote. “Louisiana’s defense of its admitting privileges law and its attack on third-party standing are both rife with mischaracterizations about physicians who provide abortion—in particular, their interests and commitment to their patients. The state impugns their motives, and the court of appeals questioned their good faith.”

It’s not just abortion rights advocates and providers arguing that the stakes in June Medical Services are too high for the Court to get wrong. A group of former federal judges and U.S. Department of Justice officials warned the Roberts Court that a decision to reconsider Whole Woman’s Health and the ability of abortion providers to sue on behalf of their patients would “have destabilizing effects that would tend to undermine the rule of law.” The nonpartisan American Bar Association filed its own amicus brief to argue that the rule of law requires lower courts follow Whole Woman’s Health as precedent. “This case raises significant concerns about adherence to basic rule of law principles and, in particular, the manner in which the United States Court of Appeals for the Fifth Circuit treated both this Court’s decision in Whole Woman’s Health v. Hellerstedt and the district court’s decision below,” the brief states.

“The integrity of the American legal system depends on our lower courts applying precedent faithfully, following ‘both the words and music of Supreme Court opinions,’” the ABA brief continues. “It is particularly important that the lower courts hew closely to precedent when addressing politically charged issues that are the subject of intense public debate. No matter how deeply held, and morally grounded, one’s disagreement with this Court’s precedents may be, the rule of law requires that lower courts strictly apply this Court’s directives, rather than avoid their application.”

It’s no small matter to have the largest professional organization of lawyers and judges argue, along with former Justice Department officials and federal judges, that the Fifth Circuit is engaging in politicking rather than judging in June Medical Services. They are also warning, if obliquely, that the Roberts Court will be doing the same should it side with Louisiana in this case.

Chief Justice John Roberts is no doubt the target audience for these briefs, given his potential swing vote. His legacy, and the legitimacy of the Court itself, is another of the high stakes in this case. But to uphold the legitimacy of the Court, Roberts will have to cast the first substantive pro-choice vote of his career. Will he? We’ll know next summer, when the Court is expected to issue its decision in June Medical Services.