In a 5-4 decision, the US Supreme Court on Monday rejected Russell Bucklew’s challenge regarding the use of lethal injection in the execution for his murder conviction in Missouri.

Two weeks before his scheduled execution, Bucklew raised the issue of his rare medical condition, cavernous hemangioma, claiming the use of pentobarbital, a chemical found in the injection formula, would cause blood clots and lead to a feeling of suffocation for over four minutes. Bucklew alleged that this form of execution was a violation of the Eighth Amendment. The court ultimately rejected Bucklew’s challenge because he is unable to present a reasonable alternative that would cause less pain and suffering.

Bucklew suggested being executed by breathing in pure nitrogen, but the court reasoned that this method has been untested in Missouri and would not suffice as a reasonable alternative to the lethal injection. The court’s decision now establishes a precedent where death row inmates must present and defend an alternative method for a less painful execution.