When does pain in an execution become “cruel and unusual punishment”? According to a 5-4 Supreme Court decision authored by Justice Neil Gorsuch, only when the state deliberately “superadds … terror, pain, or disgrace.” The conservative wing carried the day in Bucklew v Precythe, freeing Missouri to put the defendant to death via lethal injection despite a medical condition that could make the process more painful:

The Supreme Court made it clear on Monday that the U.S. Constitution does not guarantee a prisoner sentenced to capital punishment “a painless death,” paving the way for the execution of a convicted murderer who sought to die by lethal gas rather than lethal injection because of a rare medical condition. …

In a decision written by conservative Justice Neil Gorsuch, the court ruled 5-4 that Bucklew had failed to present enough evidence for them to let him ask a lower court to allow him to be executed by lethal gas. The court’s five conservatives were in the majority and its four liberals dissented.

Referencing the history of capital punishment, Gorsuch wrote that “the Eighth Amendment does not guarantee a prisoner a painless death – something that, of course, isn’t guaranteed to many people, including most victims of capital crimes.”

Monday’s ruling was in line with a decision from 2015 in which the court rejected a challenge to Oklahoma’s method of execution by lethal injection on a 5-4 vote. In that case, the court held that inmates challenging a method of execution had to come up with an alternative option that was less painful.

Gorsuch and the court’s conservatives relied on two precedents to reach this conclusion, plus the historical record of acceptable execution methods. The precedents, Baze and Glossip, hold that pain alone does not create cruel and unusual conditions. Most forms of execution involve physical pain of some sort, and earlier methods which remain constitutionally viable sometimes involve considerable amounts of pain. Gorsuch mentions hanging in particular, which could be significantly painful depending on its effectiveness on snapping the neck.

In order to qualify as cruel and unusual, a defendant has to show that the state has “a feasible and readily implemented alternative method that would significantly reduce a substantial risk of severe pain and that the State has refused to adopt without a legitimate penological reason,” Gorsuch writes in the summary. Russell Bucklew failed to demonstrate that his preferred method — nitrogen hypoxia — was either feasible or readily implemented, Gorsuch ruled, despite delaying his execution for five years through this challenge.

Besides, Gorsuch summarized, Bucklew never proved it would be less painful anyway:

Even if nitrogen hypoxia were a viable alternative, neither of Mr. Bucklew’s theories shows that nitrogen hypoxia would significantly reduce a substantial risk of severe pain. First, his contention that the State may use painful procedures to administer the lethal injection, including forcing him to lie flat on his back (which he claims could impair his breathing even before the pentobarbital is administered), rests on speculation unsupported, if not affirmatively contradicted, by the record. And to the extent the record is unclear, he had ample opportunity to conduct discovery and develop a factual record concerning the State’s planned procedures. Second, Mr. Bucklew contends that while either method will cause him to experience feelings of suffocation for some period of time before he is rendered fully unconscious, the duration of that period will be shorter with nitrogen than with pentobarbital. But nothing in the record suggests that he will be capable of experiencing pain for significantly more time after receiving pentobarbital than he would after receiving nitrogen. His claim to the contrary rested on his expert’s testimony regarding a study of euthanasia in horses that everyone now agrees the expert misunderstood or misremembered.

Sound compelling? Don’t make up your mind just yet. Justice Stephen Breyer wrote the dissent for the liberal wing, objecting to every line of argument in Gorsuch’s governing opinion. Breyer takes special objection to the contention that Bucklew didn’t prove his pain would be unusual nor that he met the standard for finding a feasible and readily available alternative. The state of Missouri already allows nitrogen hypoxia as an alternative, Breyer argued:

Missouri law permits the use of this method of execution. See Mo. Rev. Stat. §546.720 (2002). Three other States—Alabama, Mississippi, and Oklahoma—have specifically authorized nitrogen hypoxia as a method of execution. See ante, at 22, n. 1. And Bucklew introduced into the record reports from Oklahoma and Louisiana indicating that nitrogen hypoxia would be simple and painless. These reports summarized the scientific literature as indicating that there is “no reported physical discom[fort] associated with inhaling pure nitrogen,” App. 742, that the “onset of hypoxia is typically so subtle that it is unnoticeable to the subject,” id., at 745, and that nitrogen hypoxia would take an estimated “seventeen-to-twenty seconds” to render a subject unconscious, id., at 746–747. The Oklahoma study concluded that nitrogen hypoxia is “the most humane method” of execution available. Id., at 736. And the Louisiana study stated that the “[u]se of nitrogen as a method of execution can assure a quick and painless death of the offender.” Id., at 746.

How then can the majority conclude that Bucklew has failed to identify an alternative method of execution? The majority finds Bucklew’s evidence inadequate in part because, in the majority’s view, it does not show that nitrogen hypoxia will “significantly reduce” Bucklew’s risk of pain as compared with lethal injection. Ante, at 23. But the majority does not dispute the evidence suggesting that nitrogen hypoxia would be “quick and painless” and would take effect in 20 to 30 seconds. The majority instead believes that “nothing in the record” suggests that lethal injection would take longer than nitrogen gas to take effect. Ante, at 26. As I have already explained, the majority reaches this conclusion by overlooking considerable evidence to the contrary—such as Dr. Zivot’s testimony that Bucklew’s pain would likely prove “prolonged,” App. 234, that lethal injection would not “result in ‘rapid unconsciousness,’” id., at 233, and that from the time of injection to “Mr. Bucklew’s death several minutes to as long as many minutes later, Mr. Bucklew would be highly likely to experience . . . the excruciating pain of prolonged suffocation,” id., at 222. In discounting this evidence, the majority simply fails “to adhere to the axiom that in ruling on a motion for summary judgment, the evidence of the nonmovant is to be believed, and all justifiable inferences are to be drawn in his favor.” Tolan, 572 U. S., at 651 (internal quotation marks and alteration omitted).

Breyer also argues that Glossip didn’t require Bucklew to explain all of this to the court in the first place. The burden should have been on the state to prove it had no other feasible and readily available option:

Perhaps Bucklew did not provide these details. But Glossip did not refer to any of these requirements; today’s majority invents them. And to insist upon them is to create what, in a case like this one, would amount to an insurmountable hurdle for prisoners like Bucklew. That hurdle, I fear, could permit States to execute even those who will endure the most serious pain and suffering, irrespective of how exceptional their case and irrespective of how thoroughly they prove it. I cannot reconcile the majority’s decision with a constitutional Amendment that forbids all “cruel and unusual punishments.”

If Missouri already allows for nitrogen hypoxia, why not allow the defendant to choose it? Surely over the course of this five-year challenge, Missouri could have spent less time and fewer resources by making the nitrogen-hypoxia option available to Bucklew. Their decision to defend lethal injection of pentobarbitol as the method may not be unconstitutional … but insisting on that method for Bucklew and fighting it to the Supreme Court is a mystifying decision nonetheless. Perhaps Bucklew would have objected to both methods had he been given the option, but once he’d made his legal play, Missouri could have easily short-circuited the challenge by giving Bucklew what he said he wanted. Wouldn’t that have provided justice to the families of Bucklew’s victims more promptly?

That’s a question for Missouri, though, not the Supreme Court. The basic premise of Gorsuch’s opinion is well grounded, even if Missouri’s judgment could be called into question. This decision will likely act as a disincentive to other such challenges as Breyer predicts, but only to the extent that those challenges would have failed anyway.