Those who favor capital punishment because of its supposed deterrent effect do not favor strengthening that effect by restoring the practice of public executions. There has not been one in America since 1937 (a hanging in Galena, Mo.) because society has decided that state-inflicted deaths, far from being wholesomely didactic spectacles, are coarsening and revolting.

Revulsion is not an argument, but it is evidence of what former chief justice Earl Warren called society’s “evolving standards of decency.” In the essay “Reflections on the Guillotine,” Albert Camus wrote, “The man who enjoys his coffee while reading that justice has been done would spit it out at the least detail.” Capital punishment, say proponents, serves social catharsis. But administering it behind prison walls indicates a healthy squeamishness that should herald abolition.