It’s like finding a gem among a rubble of stones. Buried in the voluminous pages of Supreme Court justices’ opinions in a recent case on the death penalty was a gem in a concurring opinion written by Justice John Paul Stevens.

Stevens joined with seven other justices in upholding the constitutionality of the three-drug protocol that Kentucky and other states use in executions by lethal injection. But he went a step beyond this question to the heart of issue: questioning the reasons for continuing capital punishment.

He concluded, after examining the reasons, that the “death penalty represents ‘the pointless and needless extinction of life with only marginal contributions to any discernible social or public purposes.’ ” The time has come for the Supreme Court and legislatures to dispassionately consider “the benefits” of capital punishment, he said.

Stevens said three purposes for the death penalty were identified in a 1976 court decision that upheld capital punishment: incapacitation, deterrence and retribution. And he took issue with all three.

Incapacitation might have been a legitimate rationale in 1976, he said. But the rise in state laws providing life in prison without the possibility of parole shows that “incapacitation is neither a necessary nor a sufficient justification for the death penalty.”

In other words, society can be protected by keeping someone in prison for the rest of his or her life.

Second, deterrence as a justification for the death penalty is also questionable, Stevens said. In spite of three decades of research, “there remains no reliable statistical evidence that capital punishment in fact deters potential offenders,” he wrote. “In the absence of such evidence, deterrence cannot serve as a sufficient penological justification for this uniquely severe and irrevocable punishment” of death.

This leaves the third rationale, retribution, which Stevens said “animates much of the remaining enthusiasm for the death penalty.” While this “thirst for vengeance” is a response to heinous crimes, he noted, another trend in society in recent years “undermines the very premise on which public approval of the retribution is based.”

Stevens said society has moved away from “public and painful retribution” toward “more humane forms” of punishment. “State-sanctioned killing is therefore becoming more and more anachronistic,” he wrote. “We have adopted increasingly less painful methods of execution and then declared previous methods barbaric and archaic.”

In other words, the movement to find “more humane” ways of execution, such as lethal injection, is an attempt to sanitize a killing process that that our conscience is telling us is unacceptable.

Stevens also expressed three other concerns about capital punishment. One is depriving a defendant of a trial by jurors who represent a “fair cross-section of the community.”

His second concern is the risk of error in capital cases. “Whether or not any innocent defendants have been executed, abundant evidence accumulated in recent years has resulted in the exoneration of an unacceptable number of defendants found guilty of capital offenses,” he said.

And the third concern mentioned is “the risk of discriminatory application of the death penalty.”

Stevens concluded: “Full recognition of the diminishing force of the principal rationales for retaining the death penalty should lead this court and legislatures to re-examine the question recently posed by Professor Salinas, a former Texas prosecutor and judge, ‘Is it Time to Kill the Death Penalty?’ ”

What Stevens wrote in his opinion has been said before, but he has capsulated it in a way that should prompt all of us to reconsider the justification for retaining capital punishment.

Three years ago the U.S. Catholic bishops reaffirmed that the death penalty is “unnecessary and unjustified in our time and circumstances.” The bishops mentioned several reasons for abolishing capital punishment:

It “violates respect for human life and dignity”; “state-sanctioned killing in our names diminishes all of us”; it is “deeply flawed” and is “prone to errors”; and “we have other ways to punish criminals and protect society.”

It’s time to come to the realization that the death penalty is a “pointless and needless extinction of life.”