For a decade, the effort to abolish the death penalty in this country was focused on the U.S. Supreme Court. It was argued that the death penalty was inherently unconstitutional because it contravened the "evolving standards of decency which mark the progress of a maturing society," and therefore amounted to the cruel and unusual punishment proscribed by the eighth amendment to the Constitution of the United States. When the Supreme Court finally agreed to address this question in 1972, only Justices Marshall and Brennan agreed with the abolitionist position.

The Georgia statute before the Court in this 1972 case I classified first degree murder, rape, and armed robbery as capital crimes and left the decision whether to impose the death penalty in lieu of life imprisonment entirely to the discretion of the jury. Three members of the Supreme Court were convinced such statutes did, indeed, create a "substantial likelihood" that the death penalty would be imposed arbitrarily, and they joined with Justices Marshall and Brennan, forming a majority of five, to strike down the Georgia statute and virtually all the state statutes then in effect. 

Between 1972 and 1976, 35 states reenacted the death penalty in response to the Furman decision. However, the states responded to the Furman opinion in two entirely different ways. Some states tried to minimize the risk of arbitrariness by requiring the imposition of the death penalty for certain crimes. These socalled mandatory statutes generally applied to certain specified types of homicides, such as those committed by a person serving a life term or those involving the killing of a police officer. The other response to Furman was to preserve some degree of discretion but to reduce the risk of arbitrariness through normative constraints; the usual model was a separate sentencing hearing at which the judge or jury would consider evidence offered in aggravation and mitigation and would decide whether to impose the death penalty according to specified statutory criteria, a process that was policed by appellate review. 

Richard J. Bonnie & C. Robert Showalter, Psychiatrists and Capital Sentencing: Risks and Responsibilities in a Unique Legal Setting, 12 Bulletin of the American Academy of Psychiatry & the Law 159–167 (1984).