THE STATE of Arizona executed Joseph R. Wood III on Wednesday. For those Americans who, as we do, consider the death penalty to be a dehumanizing punishment unworthy of our advanced society, that sentence should be enough to elicit profound moral discomfort. Then there was the way it happened: Executioners pumped Mr. Wood with a two-drug regimen meant to lull him toward death peacefully and quickly. Instead, he remained alive for nearly two hours, gasping and snorting, as his lawyer frantically appealed to a judge to call off the botched execution.

Mr. Wood’s was the third execution this year that did not go as planned. And it is not the most egregious example. That would be the April execution of Clayton Lockett by the state of Oklahoma in which prison officials improperly inserted an IV into the inmate’s arm. After the drugs failed and Mr. Lockett convulsed, clenched his teeth, attempted to speak and struggled with the gurney to which he was strapped, supervisors tried to call off the execution. Too late: Mr. Lockett finally perished after suffering a heart attack. Arizona’s two-drug procedure is different from Oklahoma’s three-drug regimen but similar to the drug combination Ohio used this year in another lengthy execution.

The death penalty in the United States is in crisis for many reasons. Most states now use injected drugs to kill death-row inmates, and those drugs are in short supply as European manufacturers attempt to distance themselves from U.S. executions. States have been left to concoct novel combinations of sedatives, anti-convulsants and anesthetics and administer them without the help of professionals, who object to state-sponsored life-taking.

Meanwhile, a major reason the country has moved away from antique-seeming execution methods — firing squads, hanging, the gas chamber and the electric chair — toward lethal injection is that intravenous poisoning is less unpleasant for the public. The nation has moved from treating executions like attractive public spectacles to being disgusted by the act of purposely ending a human life.

We argue that the public’s increasing aversion should be based on concerns about issues deeper than just the method of killing inmates. There are a variety of practical objections: The death penalty is extremely expensive to administer; it is often applied to men with diminished mental capacity or other mental disorders. Racial disparities in death penalty sentencing and too-frequent death-row exonerations demonstrate that the criminal justice system has not applied the ultimate punishment fairly. Then there is the simple fact that this complex, costly and unattractive system is wholly unnecessary to punish even depraved criminals. Any combination of these factors points to the truth that the death penalty in the United States is deeply unwise. It is, as practiced, cruel and unusual.

Since the late 1990s, the number of executions in the United States has dropped significantly, as has the proportion of Americans who approve of the punishment. We hope these are signs of the nation’s moral maturation. As abhorrent as spectacles like the execution of Mr. Wood are, they could at least serve the purpose of accelerating that process.