On June 29, 1972, the U.S. Supreme Court effectively struck down the death penalty in Furman v. Georgia. 43 years later to the day, in Glossip v. Gross, the justices saved it from one existential threat—but doomed it to another.

Had the Court ruled in favor of three death-row inmates in Glossip, which challenged Oklahoma’s lethal-injection protocol, it would have been a historic shift: Never before has the Supreme Court struck down a state’s chosen method of execution as unconstitutional.

Instead, the justices upheld the use of midazolam, a sedative linked to three botched executions in the past 18 months. “Because capital punishment is constitutional, there must be a constitutional means of carrying it out,” Justice Samuel Alito wrote for a 5-4 majority, ruling that the condemned inmates failed to prove that the drug carried a “substantial risk of harm.” In the principal dissent, Justice Sonia Sotomayor rejected Alito’s logic entirely. “Nothing compels a State to perform an execution,” she argued. “It does not get a constitutional free pass simply because it desires to deliver the ultimate penalty; its ends do not justify any and all means.”

The real debate, however, went far beyond sedatives and protocols. In a surprise move, Justices Stephen Breyer and Ruth Bader Ginsburg filed a separate dissent that called on the Court to revisit the death penalty’s constitutionality.

In 1976, the Court thought that the constitutional infirmities in the death penalty could be healed; the Court in effect delegated significant responsibility to the States to develop procedures that would protect against those constitutional problems. Almost 40 years of studies, surveys, and experience strongly indicate, however, that this effort has failed. Today’s administration of the death penalty involves three fundamental constitutional defects: (1) serious unreliability, (2) arbitrariness in application, and (3) unconscionably long delays that undermine the death penalty’s penological purpose. Perhaps as a result, (4) most places within the United States have abandoned its use.

In the 41 pages that followed, Breyer explained why he believed it was “highly likely” that the death penalty violated the Eighth Amendment. “At the very least, the Court should call for full briefing on the basic question.” Two weeks later, in the first capital case after Glossip, David Zink offered them the means to do so. In his last-minute petition to the Court, Zink presented a question that the Court had not heard in over four decades:

Whether the death penalty today violates evolving standards of decency and concepts of human dignity embodied in the prohibition against cruel and unusual punishment and the Eighth Amendment as applied to the states by the Fourteenth Amendment?

Later that night, the Supreme Court denied Zink’s petition; the state of Missouri executed him at 7:33 p.m. local time. Neither Breyer nor Ginsburg offered any public dissent.