This ruling was the third since 2002 that narrowed the crimes for which death can be imposed.

The case centered on a Louisiana man convicted of raping his 8-year-old stepdaughter in 1998. The attack led not only to severe emotional trauma but also internal injuries and bleeding that required extensive surgery. The man -- Patrick Kennedy -- was sentenced to death, and his subsequent appeal was first rejected on the claims that the crime was so grievous and damaging to those involved.

For capital punishment opponents, the reversal of Kennedy’s sentence represents a victory, albeit a bittersweet one. Few crimes are as emotional for all involved as the rape of a child, and to have this particular topic be the one that redefines how capital punishment is rendered is a less than ideal scenario.

"A lot of people think there should not be a death penalty because the child survives," sex crimes prosecutor Kat Bartholomew told CNN in an interview. "In my opinion, the rape of a child is more heinous and more hideous than a homicide."

But emotions aside, this move by the Supreme Court solidifies that death can be considered cruel and unusual, something so many have argued for years.  The high court has in recent years banned execution for the mentally retarded, underage killers and those deemed to have had an inadequate defense at trial.