Billy Ray Irick, who was convicted of murdering a 7-year-old Knoxville girl he was babysitting in 1985, is the next death row inmate scheduled to be executed, on Oct. 7.

Thirty-two states have the death penalty, and all of them rely at least in part on lethal injection. Fewer than a dozen regularly carry out executions, among them Alabama, Arizona, Florida, Georgia, Mississippi, Missouri, Ohio, Oklahoma, Virginia and Texas, which leads the country. The federal government also uses lethal injection but rarely carries out executions.

The Supreme Court has never declared a method of execution unconstitutional on the grounds that it is cruel and unusual. It upheld the firing squad in 1879, the electric chair in 1890 and lethal injection in 2008.

The court has made it clear over the years that the Eighth Amendment prohibits inflicting pain merely to torture or punish an inmate, drawing a distinction between a method like electrocution and old European practices such as drawing and quartering. The Constitution prohibits "unnecessary and wanton infliction of pain," the court said in 1976.

Nonetheless, U.S. states and the federal government have updated execution methods several times in efforts to find more humane ways to put condemned criminals to death.

First used by New York State in 1890, the electric chair was employed throughout the 20th century to execute hundreds and is still an option in eight states. Since 1976, 158 inmates have been executed by electrocution. It was considered humane when it was first introduced but has resulted in many horrific executions over the years.

In 2000, Florida switched from the electric chair to injection after bungled electrocutions raised concerns that the state's death penalty would be declared unconstitutional emotional graduation day at one Virginia ˼���绨���V�x�����c their social or economic standing ���顢��ʤΤ� Three bathroom youth.