"First," he writes, "it prevents involuntary physical movements during unconsciousness that may accompany the injection of potassium chloride. The Commonwealth has an interest in preserving the dignity of the procedure, especially where convulsions or seizures could be misperceived as signs of consciousness or distress. Second, pancuronium stops respiration, hastening death."
It's clear from these justifications that the state is trying to prevent discomfort not in the condemned prisoner (who, after all, is supposed to be unconscious) but in the people who witness the execution and, by extension, the general public. "Preserving the dignity of the procedure" is code for maintaining the illusion that a man the government executes is really just undergoing a medical procedure with a very high risk of fatal complications.
In the ebb and flow of American death penalty fashions, from hanging and firing squad through electrocution and the gas chamber to lethal injection, Roberts sees "an earnest desire to provide for a progressively more humane manner of death." I see an earnest desire to soothe an increasingly squeamish public.
As Fordham University law professor Deborah Denno has noted, the execution methods that are less unpleasant to watch are not necessarily less painful. "To me," she told The New York Times a few months ago, "the firing squad is the most humane and perceived to be the most brutal."
Around the same time, the Chinese government said it planned to switch from executions by gunshot to executions by lethal injection, which "is considered more humane," according to an official of the Supreme People's Court. Should that count as progress?