The justices will decide whether a state can impose the death penalty for the rape of a child, or whether that is unconstitutional cruel and unusual punishment.

Louisiana is the only state with people on death row for rape. It has two and both involve child victims: Richard Davis, condemned to die last year for raping a little girl in Caddo Parish, and Patrick Kennedy of suburban New Orleans.

Kennedy, 43, is the man at the center of Wednesday's Supreme Court case.

Kennedy, whose IQ is put at 70, is on death row for raping his 8-year-old stepdaughter in 1998 in the New Orleans suburb of Harvey. The one-time attack was described as particularly violent.

This past December, a Caddo District Court jury recommended a death sentence for Davis, who was convicted of repeatedly raping and molesting a 5-year-old girl over several months. The jury concluded that Davis, 35, repeatedly molested the little girl and also had oral sex with her. The child, who is now 8 years old and has psychological problems, testified against Davis.

Supporters of Louisiana's law argue that child rape is so evil and traumatizing that justice cries out for death. But others warn the law will further traumatize youngsters and make rapists more likely to kill their victims.

Caddo Assistant District Attorney Brady O'Callaghan said Davis was "the worst offender" and deserved the death penalty. The little girl was not Davis' first victim, O'Callaghan said.

"The victim and the community deserve the right to say that what he did was the worst thing we can imagine," O'Callaghan said today.

Davis' lawyers say he has mental problems. His case is in the early stages of appeal and is pending before the Louisiana Supreme Court.

The Louisiana Supreme Court has upheld the death penalty for Kennedy, saying children deserve special protection. Louisiana law allows the death penalty for the rape of a child 12 or younger.

The U.S. Supreme Court over the years has narrowed the circumstances for which a person could be executed.

In 1977, it ruled that a state could not execute a man who raped an adult woman. The court earlier said juveniles and the mentally retarded could not be executed. Challenges are now pending on whether lethal injection is constitutional.

"Those are obviously cases of pulling back," O'Callaghan said. "The court's composition has changed so much, so predicting how they will address this issue is tough."

Prosecutors believe child rapists should lead to an expansion of capital punishment, not a narrowing of it.

The last time someone in the U.S. was executed for something other than murder was in 1964, when a man went to the electric chair in Alabama for robbery. That same year, a man in Missouri went to the gas chamber in what was the last time someone in this country was put to death for rape.

At least five other states -- Georgia, Montana, Oklahoma, South Carolina and Texas -- have laws allowing execution for the rape of a child but no one on death row for the crime.

The Associated Press contributed to this report