An execution gone awry in Arizona on Wednesday — the first in the United States since a botched execution in Oklahoma in April — has rekindled debate nationwide about whether lethal injection is unconstitutionally cruel and unusual punishment.

But the ordeal did not move officials in Missouri to back down from any plans to carry out executions. On the contrary, the state Supreme Court on Thursday ordered what would be the eighth execution of the year.

Death by injection usually takes 10 to 15 minutes, but witnesses in Arizona said murderer Joseph R. Wood III gasped for one hour and 40 minutes on Wednesday before he died. Wood’s lawyers said it was evidence of agony; state officials and the victims’ families insisted Wood was unconscious after the first few minutes and that the noises were merely snoring.

Experts said the execution would certainly have at least a subtle effect of chipping away at the nation’s already shrinking support for capital punishment.

When states kill people with injections, “we think there is a real risk that torture will happen, and now it has repeatedly happened,” said Anthony Rothert, legal director of the American Civil Liberties Union of Missouri, which opposes the death penalty.