Witherspoon v. Illinois, 391 U.S. 510 (1968), was a U.S. Supreme Court case where the court ruled that a state statute providing the state unlimited challenge for cause of jurors who might have any objection to the death penalty gave too much bias in favor of the prosecution.

The Court said,

Whatever else might be said of capital punishment, it is at least clear that its imposition by a hanging jury cannot be squared with the Constitution. The State of Illinois has stacked the deck against the petitioner. To execute this death sentence would deprive him of his life without due process of law.

The decision in this case would cause the Supreme Court of California to order a retrial on the penalty phase in the 1972 case of California v. Anderson, and when the case was heard for the third time, would find the imposition of the death penalty was unconstitutional on the grounds of the penalty being cruel or unusual punishment, in violation of the State Constitution. The decision would become national in scale when the U.S. Supreme Court also in 1972 ruled in Furman v. Georgia that all death penalty cases were in violation of the 8th Amendment's prohibition on cruel and unusual punishment.

Witherspoon died at his home in Detroit, Michigan on Sunday March 4, 1990 after a battle with cancer.^[1]

• List of United States Supreme Court cases, volume 391