Update, May 21st, 12:10AM ET: A US Supreme Court Justice has issued an order halting the execution of Russell Bucklew. Justice Samuel Alito issued the order shortly after the a full panel of judges from the Eighth Circuit Court of Appeals, which had granted Bucklew a stay of execution a few hours earlier, reversed its decision. The stay of execution had been issued by a smaller panel of three appeals court judges. Alito has yet to explain why he intervened to stop the execution.

By the afternoon of March 21st, 1996, Russell Bucklew was in a jealous rage. The 27-year-old stole two pistols, two sets of handcuffs, and a roll of Duct tape and headed to the trailer where his ex-girlfriend, her new boyfriend, and the boyfriend’s children were staying. Bucklew shot the boyfriend, killing him. Then he fired a shot at one of the children — fortunately missing the boy — before kidnapping his ex, driving away with her, and raping her. At trial a year later he would argue that his eventual confession to investigators was unfairly coerced. But he would never deny that he did what he was convicted of — and sentenced to death for doing. As his lawyer told The Verge this morning, "Mr. Bucklew has always accepted the consequences of his actions. Nor has he ever claimed innocence."

But today, his lawyers are nonetheless struggling to save Bucklew’s life.

Tonight, at a minute after midnight Central Daylight Time, Bucklew is scheduled to be executed via lethal injection by the State of Missouri. Though no one’s arguing that Bucklew is a great and magnanimous man, his lawyers argue that Missouri’s lethal injection policies could cause Bucklew to die in a cruel and unusual way.

Late last month, Oklahoma prisoner Clayton Lockett was convicted and sentenced to death for the 1999 murder of a 19-year-old woman. When an execution drug failed to kill him — the result of a vein collapse and a shortage of lethal injection drugs available to doctors at the execution — Lockett died of a heart attack on a gurney 43 minutes after his execution began.

Lawyers are hoping to stave off a similar fate for Bucklew.

As pharmaceutical companies have backed away from having their drugs used to carry out state killings, states such as Missouri have faced a shortage of the drugs it uses to execute state prisoners. Missouri — which has had a troubling history of fiascoes related to its execution policies — and other states have thus called upon compounding pharmacies to create generic pharmaceuticals that will mimic the effects of drugs such as Nembutal, which kill prisoners through sedation. But Missouri has failed to disclose the chemical makeup of those drugs, forcing media organizations such as the Associated Press to file a First Amendment lawsuit so that the makeup of those drugs will be public. Lawyers, including Bucklew's representative Lindsay Runnels, argue that executions should be halted until such information is freely available.

"As we saw in Clayton Lockett’s case," Runnels tells The Verge, "whenever someone struggles to breathe while they’re being executed, it’s cruel and unusual and in violation of the Eighth Amendment of the US Constitution. Fundamentally, we can’t allow that to happen."

Further complicating things, according to Bucklew’s lawyer, is the man’s health.

Dr. Joel B. Zivot, an assistant professor of anesthesiology and surgery and Emory University's School of Medicine, examined Bucklew earlier this month. Detailing what he found in a signed affidavit, he writes that Bucklew suffers from extreme hypertension and that a "very large vascular mass … distorts the anatomy of Mr. Bucklew's airway." When Bucklew is strapped down to a gurney — as is protocol when someone faces lethal injection — there’s a very good possibility he won’t be able to breathe, the affidavit states. The concern, Zivot writes, is that Bucklew will suffocate before the lethal injection drug can kill him.

"The bottom line" in Bucklew’s case, Zivot writes, "is that there is no way to proceed with Mr. Bucklew's execution without a substantial risk to Mr. Bucklew of suffering grave adverse events during the execution, including hemorrhaging, suffocating, or experiencing excruciating pain."

Bucklew’s legal team filed a motion last week to delay the execution — and to film it if it occurs tonight. The filming needs to occur, they write, in case Bucklew "survives the execution and needs the taped evidence to oppose another attempt to execute him"; in case he "suffers injury and needs the evidence in support of any legal claims for damages"; or in case he "suffers a prolonged and excruciating execution or chokes and suffocates to death, and the evidence is relevant to a legal claim brought in the name of his estate."

That hasn’t gotten them far. The lawyers filed a new motion today, hoping to stay Bucklew’s execution. But as of now Missouri’s governor plans to let it commence without cameras.