Furman v. Georgia (1972)
The Supreme Court's 5-4 ruling in Furman v. Georgia brought to a halt all executions that were pending in the 39 states that had the death penalty.  At the time there were 600 people on death row, but executions were infrequently carried out.  Under review were three different cases in which the death penalty was given African-American defendants:  Lucious Jackson, who was convicted of rape in Georgia; Elmer Branch, who was convicted of rape in Texas ; and William Henry Furman, who was convicted of murder in Georgia .  Furman was robbing a house when he was surprised by the return of the resident.  He tripped while trying to escape from the house and accidentally discharged his weapon, killing the resident. The Supreme Court in a 5-4 decision held that the death penalty was imposed in such a random way that it was no longer a credible deterrent to crime and in these instances, constituted cruel and unusual punishment barred by the Eighth Amendment.  The justices were very divided in their reasoning.  One wrote that he could not permit "this unique penalty to be so wantonly and so freakishly imposed."  Others felt the death penalty had no place in contemporary society, and was disproportionately used against members of minority groups.  Dissenting justices maintained that it could only be abolished by legislatures, not by the courts. 

After this decision, 37 states rewrote their death penalty laws to make them "constitutional."   These re-drafted laws were upheld by the Supreme Court beginning with its 1976 decision in Gregg v. Georgia. 

http://www.oyez.org/cases/1970-1979/1971/1971_69_5003/