On Wednesday, Timothy McVeigh is scheduled to be executed, marking the first federal execution in almost 40 years. McVeigh was convicted of bombing the Alfred R. Murrah federal office building in Oklahoma City in 1995 and killing 168 people.

Unlike many death penalty cases, none of the factors that often lead people to oppose the death penalty — questions about innocence, racial bias, competent legal representation, economic injustice — are present in this case. Yet why have the leaders of dozens of national religious organizations (including the heads of the Reform and Conservative movements) signed a letter opposing McVeigh's execution? Because whatever benefits one might believe might accompany the death penalty, its societal costs are far too high.

One can argue that the death penalty, theoretically, is an appropriate punishment for the most horrendous crimes. In theory, the death penalty could be a strong deterrent to criminals. In theory, one can create a system that adequately protects the rights of the innocent and guarantees that there will be no falsely convicted people on death row. In theory, the justice system would be racially blind.

But we don't live in a theoretical world. We live in the real world and in the real world few, if any, of the perceived benefits of executions actually exist. In the real world, of all the possible deterrents to crime, police officers and criminologists consistently list the death penalty last in terms of effectiveness. In the real world, the state of Illinois found more people on death row had been falsely convicted than had been executed.

In the real world, in 83 percent of capital cases, the victims were white, although nationally only 50 percent of murder victims are white. In the real world, 33 mentally retarded individuals have been executed. In the real world, 70 innocent people have been released from death row in the last 30 years. In the real world, the death penalty does not work and, unlike any other punishment, it is irreversible.

Even if only one innocent person were executed, it would outweigh whatever value capital punishment might have. Therefore, state-sponsored execution is immoral, irrespective of the guilt of the offender.

Judaism recognizes the tension inherent in the death penalty. The Torah prescribes capital punishment for numerous offenses, ranging from murder to breaking Shabbat. But the Torah also recognizes the risks involved with the death penalty and immediately seeks to place limitations on its use. Thus, Deuteronomy teaches: "A person shall be put to death only on the testimony of two or more witnesses; he must not be put to death on the testimony of a single witness. Let the hands of the witnesses be the first against him to put him to death, and the hands of the rest of the people thereafter. Thus you will sweep out evil from your midst" (Deut. 17:6-7).

The rabbis of the Talmud further instruct judges to warn the eyewitnesses against perjury. Mishnah Sanhedrin teaches: "How shall one impress witnesses in a criminal case with the gravity of their position? One takes them aside and charges them, 'Be certain that your testimony is no guesswork, no hearsay, not derived at secondhand, nor by reliance on the observation even of a trustworthy person. Remember, you must face a severe cross-examination. Know that a criminal case is by no means like a civil. In the latter, he who has caused an injustice by his testimony can make monetary restitution, but in the former, the blood of the accused and his unborn offspring stain the perjurer forever."

So while, in theory, the Torah ordains the death penalty, in the real world, the rabbis placed such severe restrictions on its use that, already by the second century C.E., we find the following statement in the Mishnah: "The Sanhedrin that puts to death one person in seven years is termed tyrannical. Rabbi Eleazar ben Azariah says, One person in 70 years."

And Rabbis Akiva and Tarfon go so far as to say: "If we had been in the Sanhedrin, no one would have ever been put to death" (Mishnah Makkot 1:10).

While the debate continues, it is clear that more than 1,800 years ago, some of our most revered sages recognized the conclusion that so many of us have come to today: The death penalty, no matter what the circumstance, is a fundamentally immoral punishment.

By executing a mass-murderer, we do not lessen the level of violence in society. In fact, we contribute to it. Moreover, because capital punishment, like every human intervention, is inevitably flawed by human error, if we allow a Timothy McVeigh to be executed, we are allowing for the fact that we will put innocent people to death. And this is a price that is far too high for a moral society to bear.

On Wednesday, take a moment of silence to mourn, if not McVeigh's individual death, the fact that we, as a nation, are back in the executing business.