Arguments involving a Louisiana man's rape of his 8-year-old stepdaughter took place the same day the fractured court upheld lethal injection in the execution of condemned prisoners.
The case of Patrick Kennedy of Harvey, La., outside New Orleans represents a shift in the ongoing debate over the death penalty. In recent years, the Supreme Court has narrowed capital punishment, overturning it for murderers who are juveniles or are mentally retarded.
Chief Justice John Roberts and Justice Antonin Scalia made clear that it's time to consider that evolving standards appear to be heading in a new direction, at least on the subject of child rape.
Justice Stephen Breyer appeared cautious about a change.
"I'm not a moralist. I'm a judge," said Breyer. "As a judge, I look at the law. It seems for 43 years, no one has been executed but for murder."
Besides Louisiana, four other states allow executions of someone convicted of child rape. The other states - Montana, Oklahoma, South Carolina and Texas - have not applied the death penalty to child rapists. Missouri, led by Gov. Matt Blunt, is considering a similar law.
Kennedy's lawyer, Jeffrey L. Fisher, told the court the death penalty for child rape under Louisiana law can be applied too easily and that not enough states have enacted the death penalty for child rape to justify the Supreme Court's support for it.
The court's past cases require the presence of aggravating facts that make a person committing a particularly heinous crime eligible for the death penalty, said Fisher.
"How would you describe a particularly heinous rape of a child under 12?" asked Scalia. "What would make it particularly heinous?"
When the defendant has engaged in previous criminal activity or when the rape took place while the defendant was committing other crimes, Fisher replied.
Fisher said that a long-standing national consensus exists against capital punishment for rape, prompting disagreement from Roberts.
The trend since 1995 has been that more and more states are passing laws imposing the death penalty, said the chief justice, pointing to the states that have followed Louisiana.
You have to ask yourself the question whether that is enough, Fisher replied.
Roberts questioned how a consensus can develop among the states if the court steps in at the outset and says a death penalty for child rape is unconstitutional.
"If you knock them down one by one, it is kind of hard to get a trend going," said Roberts.
Justice Samuel Alito asked whether the worst case of child rape that can be envisioned is still less heinous than any murder that qualified for the death penalty.
Fisher urged the justices not to take the step Louisiana is urging, saying that "once you roll the line back ... it becomes extraordinarily difficult" to figure out what crimes that do not involve the victim's death qualify for the death penalty.
Justice Anthony Kennedy pointed out that treason carries the death penalty.
On the other side of the argument from Fisher, Louisiana prosecutor Juliet Clark and Texas Solicitor General R. Ted Cruz focused on what Kennedy did.
The 43-year-old convict who raped his stepdaughter at their home in 1998 is "exquisitely culpable" and he has committed a crime that is "just unspeakable," Cruz told the court.
Clark detailed the injuries of Kennedy's stepdaughter, which required surgery, arguing that a crime of such savagery warrants Kennedy's execution.
Were those injuries permanent? asked Justice John Paul Stevens.
They were not, but such cases involve psychological injuries as well, Clark said.
In the lethal injection ruling the court issued just before the Louisiana case, Stevens said for the first time that he now believes the death penalty is unconstitutional.