The risk of executing the innocent precludes the use of the death penalty. The death penalty alone imposes an irrevocable sentence. Once an inmate is executed, nothing can be done to make amends if a mistake has been made. There is considerable evidence that many mistakes have been made in sentencing people to death. Since 1973, at least 88 people have been released from death row after evidence of their innocence emerged. During the same period of time, over 650 people have been executed. Thus, for every seven people executed, we have found one person on death row who never should have been convicted. These statistics represent an intolerable risk of executing the innocent. If an automobile manufacturer operated with similar failure rates, it would be run out of business. Our capital punishment system is unreliable. A recent study by Columbia University Law School found that two thirds of all capital trials contained serious errors. When the cases were retried, over 80% of the defendants were not sentenced to death and 7% were completely acquitted. Many of the releases of innocent defendants from death row came about as a result of factors outside of the justice system. Recently, journalism students in Illinois were assigned to investigate the case of a man who was scheduled to be executed, after the system of appeals had rejected his legal claims. The students discovered that one witness had lied at the original trial, and they were able to find the true killer, who confessed to the crime on videotape. The innocent man who was released was very fortunate, but he was spared because of the informal efforts of concerned citizens, not because of the justice system.In other cases, DNA testing has exonerated death row inmates. Here, too, the justice system had concluded that these defendants were guilty and deserving of the death penalty. DNA testing became available only in the early 1990s, due to advancements in science. If this test...