Over time, research into various crimes punishable by the death penalty changed throughout Supreme Court cases, appellate processes and also the Constitution. In 1986, the Supreme Court ruled it unconstitutional to execute the insane; in 1989, the Supreme Court also ruled it unconstitutional to execute mentally retarded persons. Also, in 1987, during McCleskey v. Kemp, the rise in racial discrimination became more eminent to the community. Only six years after the high jump in support, its highest at eighty percent in 1994, the support for capital punishment drops to its lowest in nineteen years. In this same poll, Americans believe that one in every five people executed are innocent. Another informal moratorium began in September of 2007, awaiting the Supreme Court’s decision on the constitutionality of the method of lethal injection. However, the moratorium was cut short when the executions began again in April of 2008, after the Supreme Court ruled in favor of lethal injection.