The campaign to roll back abortion rights was temporarily stalled Monday, with a narrowly divided Supreme Court ruling.

The court struck down a Louisiana law that would have eliminated access to abortion for most women without officially making the procedure illegal, an obvious legal end-run around Roe v Wade. The deciding vote in the 5-4 decision came from Chief Justice John Roberts, who said he was bound to overturn the law by the principle of “stare decisis” (Latin for “to stand by things decided”), which means that courts should overturn established precedent only if they have extraordinary reasons.

Four years ago, a five-justice majority struck down a Texas law that would have required doctors who perform abortions to have admitting privileges at local hospitals. This was said to be in the interest of women’s health, even though abortion complications are extremely rare. But it would have resulted closing most of the state’s abortion providers, making the procedure impossible for many women to access.

The majority ruled that the law would place a “substantial burden” on women seeking to exercise their constitutional rights and struck it down. The Louisiana law was identical to the Texas law, crafted to take another shot at the court, which had added two new justices. Roberts had been on the losing side in the earlier case, but now he said he felt obligated to switch sides and uphold an established precedent, even one he considered “wrongly decided.” Stare decisis, Roberts said,  “requires us … to treat like cases alike.”

The decision was a disappointment for the activists who have worked for decades to build a Supreme Court that would make abortion a matter for states to decide and not a constitutional right. But it gives only temporary relief to abortion rights supporters.

Roberts wrote that his vote was based entirely on honoring precedent. He did not give a hint about how different a law would have to be for him to feel that he wasn’t bound to uphold it.

And the chief justice’s argument about stare decisis did not persuade the two newest members of the court, Justices Neil Gorsuch and Brett Kavanaugh, who told senators during their confirmation hearings that they were not interested in overturning already-decided cases. Gorsuch said precedent was “the anchor of the law,” and Kavanaugh said not only that following precedent is good judicial policy, but also that “it is constitutionally dictated to pay attention and pay heed to rules of precedent.” In both confirmations, Maine Sen. Susan Collins said she based her support in part on these assurances.

But neither Gorsuch nor Kavanaugh expressed any concern about overturning a precedent, even one that involves a state law that was written expressly to give the Supreme Court a do-over on a case it had just decided a few months before the last presidential election. If court rulings follow election results that closely, no one will ever be able to rely on what’s supposed to be the last word on a controversy.

In this decision, Roberts did not vote in favor of abortion rights – he voted to restore some of the Supreme Court’s lost credibility as a non-political branch of government. Roberts’ vote is a nice break in a polarized environment, but the campaign to use the courts to roll back abortion rights is far from over.