Based on the proven rate of exonerations among U.S. death-row prisoners in the past two decades
U.S. courts appear to have an error rate in capital cases of between 2.5 percent and 4 percent. (source)
Since the reinstatement of the death penalty in the U.S. in 1976, more than 140 men and women have been released from Death Row, some only minutes away from execution (source). That’s a not insignificant number of wrongful convictions. DNA testing has a lot to do with it, and one can see similar patterns in non-capital cases:
researchers examining biological evidence from hundreds of Virginia rape convictions between 1973 and 1987 determined that new DNA testing appeared to exonerate convicted defendants in 8 percent to 15 percent of cases. (source)
Taking into account that DNA evidence is not available in all criminal cases or in all types of crimes, the real error rate in U.S. justice is probably even higher. One can only imagine the rates in other, less developed criminal justice systems in other parts of the world.
Of course, miscarriages of justice are particularly painful in capital cases where we are not just talking about wrongful convictions but also wrongful executions. The latter will be less numerous than the former given the sometimes extended periods of time between conviction and execution, time which can and sometimes is indeed used to expose miscarriages of justice. Still, we have to assume that there’s also a significant number of wrongful executions: DNA is not always available – it depends on the circumstances of the homicide – and other means of proving innocence are not always successful even when lawyers have years to do their work.
This is why I believe that any error rate, however small, should be unacceptable in the application of capital punishment. You cannot correct a wrongful execution. You can, to some extent, correct a wrongful imprisonment: you can release people, even if you can’t give them back their lost years. You can’t bring people back from the dead. Given the evidence of error rates, it must be beyond doubt that the criminal justice system in the U.S. – and elsewhere as well – has executed innocent people. The most prominent known cases are those of Carlos DeLuna and Cameron Todd Willingham. And nothing Scalia or any other delusional proponent of the death penalty believes changes the facts.
It’s my opinion that capital punishment as such is unacceptable, even if the error rate were 0, but an error rate higher than zero makes it all the more unacceptable. And it should make it unacceptable even for proponents of capital punishment. After all, if you think that an error rate of, say, 2% is OK, then why not 2.1? 2.2? And so on. Human life loses all value once you accept an error rate, however small, and most if not all proponents of the death penalty are motivated by their love of human life.
More posts in this series are here.