Biblical law mandates the death penalty for 36 offenses. These include a broad range of crimes from murder to kidnapping, adultery to incest, certain forms of rape, idolatrous worship and public incitement to apostasy, from disrespecting parents to desecrating the Sabbath.
The Reform Movement, however, has followed rabbinic interpretations that effectively abolished the death penalty centuries ago. Mishnah Sanhedrin 4:5 stresses the importance of presenting completely accurate testimony in capital cases, for any mistakes or falsehoods could result in the shedding of innocent blood. If any perjury were to cause an execution, "the blood of the accused and his unborn offspring stain the perjurer forever."
The passage goes on to liken wrongful executions to Cain killing Abel, concluding that - it is for this reason that God created only one human in the beginning, a token that he who destroys one life, it is as though he had destroyed all humankind; whereas he who preserves one life, it is as though he preserved all humanity."
Furthermore, the rabbis of the Talmud ruled that capital cases required a 23-judge court, while only three judges sat for non-capital cases (Mishnah Sanhedrin 4:1). Two or more eyewitnesses were required to testify to the defendant's guilt, bearing in mind that it was their hands that would, "be the first against him to put him to death" (Deuteronomy 17:6-7). In a capital case, a one-vote majority could acquit a defendant, but could not convict. Furthermore, if there was a mere one-vote majority or if any judge was undecided, additional judges were added in pairs until the majority ruled against conviction, or until one judge in favor of conviction was persuaded to err on the side of innocence (Mishnah Sanhedrin 5:5). In practice, these guidelines made applying the death penalty nearly impossible.
In another passage, the rabbis show distaste for executions. "Said one: The Sanhedrin (Supreme Court) that puts to death one person in seven years is termed tyrannical. Rabbi Eleazar Ben Azariah says, ‘One person in seventy years.’ Rabbi Tarffon and Rabbi Akiba say, ‘If we had been in the Sanhedrin, no one would have ever been put to death.’ Rabban Simeon Ben Gamaliel says, ‘They would have thereby increased the shedders of blood in Israel (Mishnah Makkot 1:10).’"
While the last line indicates a belief that the death penalty, if carried out judiciously, can be a deterrent, prevailing Jewish thought in every movement has followed the previous opinions, which either oppose the death penalty outright, or allow for it only in the most extreme -- once in seventy years -- circumstances. Following this line of thinking, the major Jewish movements in the United States all have specific policy supporting either abolition of the death penalty, or a moratorium on its use.