But don't just take my word for it. Take the word of retired Justice John Paul Stevens. In 1976, the Ford appointee also voted in Gregg to reinstate the death penalty. In 2008, however, in a Kentucky case styled Baze v. Rees, he announced that he had changed his mind. Evaluating capital punishment for nearly a third of a century on the highest court in the land, Justice Stevens wrote, had allowed him to reach certain conclusions about the misapplication of the death penalty. He emphasized four specific concerns:

Litigation involving both challenges for cause and peremptory challenges has persuaded me that the process of obtaining a “death qualified jury” is really a procedure that has the purpose and effect of obtaining a jury that is biased in favor of conviction. Our former emphasis on the importance of ensuring that decisions in death cases be adequately supported by reason rather than emotion has been undercut by more recent decisions placing a thumb on the prosecutor’s side of the scales. A third significant concern is the risk of discriminatory application of the death penalty. While that risk has been dramatically reduced, the Court has allowed it to continue to play an unacceptable role in capital cases. Whether or not any innocent defendants have actually been executed, abundant evidence accumulated in recent years has resulted in the exoneration of an unacceptable number of defendants found guilty of capital offenses. (Citations omitted by me)

The systemic problems with capital punishment that Lewis Powell mentioned in 1991, and that Justice Blackmun identified in 1994, had not been cured by the time Justice Stevens identified them in 2008 (and again in 2010, in The New York Review of Books, in a review in which he lamented the Court's broadened application of capital punishment). Nor has the Supreme Court addressed, let alone resolved, these problems in the years since Justice Stevens retired. Just last month, the justices refused even to hear an Alabama case in which an elected judge overrode a jury's sentencing verdict and imposed a death sentence.

Three Republican-nominated justices, three men of moderation, among the least ideological the Court has produced in the past 50 years, all came late in life to regret their early doctrinal support for capital punishment. Retired Justice Sandra Day O'Connor, the first woman on the Court, a nominee of President Ronald Reagan, also questioned the use of capital punishment near the end of her tenure on it. She had concerns about the execution of the innocence, she said, and she acknowledged the equal protection implications of the fact that rich capital defendants get better legal representation than poor ones.

Now let's list the Supreme Court justices of our time, or of our parents' time, who started out as advocates for the abolition of capital punishment but whose experience with capital cases on the High Court over decades caused them to support the death penalty. Alas, we can't do it. Not a single justice has ever been so converted. Is that not telling? Exposure to capital cases doesn't cause these smart and honorable men and women to gain confidence in the neutral and accurate application of the death penalty, because no such confidence is warranted—because no such application exists.