In June of 2000, a search conducted at the University of Columbia by a group headed by Professor James Liebman, made sensations as it published the results on the judicial errors in capital punishment cases.

Liebman’s search, entitled "A Failing System: The rate of Errors in Capital Punishment Cases from 1973 to 1995," shows that in 68% of the appeals of capital punishment cases at the state or federal level, errors appear such as to provoke their cancellation. Only 18% of the repeated proceedings conclude with a second death sentence, moreover many of these proceedings are again cancelled by appeals. 9% of the cases arrive to a complete acquittal and to the liberation of the condemned. A second search carried out by the same group was published last February 11th. The results of the new search confirm the fallacy of the death penalty system in the USA.

The second search, entitled "A Failing System: Why are There so Many Errors in Capital Punishment Cases and What Must be Done" aims to specify the causes of the judicial errors and suggests reforms that can reduce the number of errors. The study brings to light a certain number of factors that produce errors, starting with the policy, the race, and by the desire of reducing the crime in the courts. A constant result, simple and important, is that the increasing number of death sentences, increase the number of errors. Going from situations in which the rate of capital punishment is the lowest to those in which it is the highest, the rate of judiciary errors multiply by six times and reach 80% of the cases. More and more frequently, states are beginning to assign indiscriminately the death penalty for every type of murder, more frequent is the serious occurrence of judicial errors and the probability of finding those once condemned to death, now innocent.

The probability of emerging judicial errors grows where there is the highest number of Caucasian deaths, in the regions where the greatest percentage of the population are of color, in the places in which a minor percentage of criminals are prosecuted, in places where the election of the judges is more affected by political factors, and where the judges that want to be elected have one eye watching the justice, and the other in pursuit of public opinion.

Both searches demonstrate without a shadow of a doubt that in the United States of America the death penalty system is permeated by substantial judicial errors, errors that cannot be all revealed and corrected, and that with all likelihood, brings to execution a number of persons completely innocent and a significant number of people despite their guilt, would not, however, have received the death penalty.