The timing and contrast were striking: As President Barack Obama introduced Judge Sonia Sotomayor to the nation as his U.S. Supreme Court nominee, Justice Antonin Scalia, sitting on the high court bench, read parts of a 5-4 decision overruling a 23-year-old precedent on the right to counsel.

It was business as usual for the justices Tuesday but also a reminder of the importance of one vote on a Court still closely divided in key areas of the law.

In one of three decisions issued to an unusually sparse courthouse audience, the majority in Montejo v. Louisiana (pdf) overruled Michigan v. Jackson, the 1986 decision that bars police from initiating interrogation of a criminal defendant once he or she has asked for a lawyer at an arraignment or a similar proceeding.

The viability of Michigan v. Jackson was not the original issue raised by Jesse Jay Montejo's petition to the Court. Montejo, convicted of first-degree murder and sentenced to death, was challenging a Louisiana Supreme Court ruling that had upheld the introduction into evidence of a letter of apology by Montejo to his victim's widow. The letter was written after Montejo was assigned counsel at a preliminary hearing held 72 hours after his arrest and after he had waived his Miranda rights.

Montejo had argued that under the rule of Jackson, the letter should have been suppressed. But the state high court held that Jackson's protection was triggered only when a defendant actually requested a lawyer or asserted his Sixth Amendment right to counsel. Because Montejo stood mute at his hearing while the judge appointed counsel, the court said he had made no request or assertion.

But the question of whether Jackson should be overruled was raised by Justice Samuel Alito Jr. during March arguments in Montejo's case. The high court ordered additional briefing on the issue.

Scalia said Jackson was "poorly reasoned, has created no significant reliance interests and is ultimately unworkable."

Because of protections created by the Court in Miranda and related cases, he said, "There is little if any chance that a defendant will be badgered into waiving his right to have counsel present during interrogation."

Chief Justice John Roberts Jr. and Justice Clarence Thomas joined the majority. Alito filed a concurring opinion that was joined by Justice Anthony Kennedy. Justice John Paul Stevens, joined by justices David Souter and Ruth Bader Ginsburg, filed a dissenting opinion; Justice Stephen Breyer also filed a dissenting opinion.

Stevens read portions of his dissent from the bench -- the first of the term -- and called the overruling of Jackson "unwarranted." He said the Miranda warnings were not adequate to inform a defendant of his Sixth Amendment right to have a lawyer present at all critical stages.

In another 5-4 ruling, the high court struck down a New York Court of Appeals decision upholding a state law that eliminated state court jurisdiction over damages suits filed by prisoners against state correction officers.

This time the 5-4 lineup in Haywood v. Drown (pdf) was reversed with Stevens writing the majority opinion holding that the state law was trumped by the Constitution's supremacy clause. Kennedy was the fifth vote and Thomas led the dissenters.

And finally, in Abuelhawa v. U.S. (pdf), Souter led a unanimous Court in holding that someone who makes a telephone call to a drug dealer in making a misdemeanor drug buy does not "facilitate" the dealer's felony of drug distribution.

Under the government's argument, Abuelhawa's use of the phone would have subjected him to six felony counts and a potential 24 years in prison even though buying the same drugs minus the phone would have meant a two-year sentence, according to Souter.