The court said it will reopen the question of whether executing very young killers violates the Constitution's ban on "cruel and unusual punishment." Currently, states that allow the death penalty may impose it on killers who were 16 or 17 at the time of their crimes.
The Supreme Court Monday also:
The death penalty case, which will probably be decided in the court's next term, continues the high court's reexamination of who belongs on death row and how the death penalty is carried out. The court's calendar for the current term is apparently full, with oral arguments scheduled through April.
The court agreed to hear the case of a Missouri man who was 17 when he robbed a woman, wrapped her head in duct tape and threw her off a railroad bridge in 1993. The state Supreme Court declared it unconstitutional to send people to their deaths for killings committed when they were younger than 18.
The 4-3 decision by the Missouri Supreme Court overturned the death sentence of Christopher Simmons, and sentenced him to life in prison instead.
"Either the justices aren't happy with that ruling and are taking the opportunity to change it or they see the Missouri case as a vehicle to create a national ban on these types of death penalty cases," said CBSNews.com Legal Analyst Andrew Cohen.
But don't read too much into the court's action Monday, he said.
"It doesn't necessarily mean that the justices now are poised to declare capital punishment unconstitutional when applied to juvenile offenders, but there is a trend in the law in that direction in this country and around the world."
In 2003, the four-member liberal wing of the court issued an unusual statement calling it "shameful" to execute juvenile killers.
"The practice of executing such offenders is a relic of the past and is inconsistent with evolving standards of decency in a civilized society," Justice John Paul Stevens wrote then. He was joined by Justices David H. Souter, Ruth Bader Ginsburg and Stephen Breyer.
The rhetoric echoed the court's 2002 ruling that it is unconstitutional to execute the mentally retarded. In both instances, the constitutional question turns on the defendants' ability to understand their situation, and their level of culpability.
Also like the retardation question, this one will involve an examination of whether the country has changed its mind about what kind of punishment is appropriate.
The court relied heavily on the actions of state legislatures in deciding to ban executions of the retarded. On that issue, the court said the large number of states that had acted on their own to ban such executions showed that the nation no longer supported the practice.
The court majority said, in effect, that times change and that the constitutionality of such executions changes with them. The 6-3 ruling drew fierce dissents from the court's three most conservative members, who view the Constitution as a more rigid document.
The American Bar Association was among groups that urged the court to clarify that people facing charges must be told by police they have a right to see an attorney.
The ruling will discourage officers from trying to elicit confessions from off-guard suspects facing charges.
Justice Sandra Day O'Connor, writing for the majority, said that the officers violated John J. Fellers' constitutional rights by deliberately eliciting information during a 15-minute interview in his home, without telling him he could see an attorney.
"This is just the first of several Miranda cases that the Court will take up this term," said Cohen, "so while this ruling certainly affirms the practice and principle of Miranda civil liberties groups probably shouldn't celebrate yet. There still are a few more opportunities for the justices to limit the scope of the doctrine."