Also on the court's right wing is Justice Samuel A. Alito Jr., 61, who joined the court in 2006 after a contentious confirmation process. Appointed by President George W. Bush, Alito worked in the Reagan Justice Department with Attorney General Ed Meese before becoming a federal judge. He credits his father, an Italian immigrant who escaped poverty through education and held a longtime position with the New Jersey state legislature, with his approach to the law.

The swing vote

Anthony M. Kennedy, 75, a Reagan appointee, joined the court in 1988 and has become the pivotal link between the conservative and liberal wings of the court, often providing the one vote needed for 5-4 majority opinions.

Kennedy often considers foreign laws when interpreting the Constitution, a practice that has brought him the hatred of the political right. James Dobson, founder of Focus on the Family, in 2003 called Kennedy "the most dangerous man in America."

Kennedy says there's a Know-Nothing aspect to the criticism. No scientist would be censured for referring to relevant scientific studies from other countries, he says, and foreign law, while not binding, can be helpful in analyzing approaches to legal issues.

The newest members

While the majority of the court's members may have Northeastern roots, there's more gender diversity than ever. Three women are on the court, including the first Latina. Sonia M. Sotomayor, 57, a self-described "Newyorkian," was born to Puerto Rican-born parents who moved to the states during World War II. Sotomayor, who joined the court in 2009, has said a judge's personal experiences "affect the facts that judges choose to see."

The court's written opinions are thought to be so complex that only a lawyer can understand them, but that's not always the case. Some opinions are lively and surprisingly vinegary. Scalia last year blasted an opinion by Sotomayor as a "gross distortion of the facts," "utter nonsense" and "unprincipled."

While their rhetoric makes it seem that the justices are at each other's throats, Elena Kagan, who joined the court in August 2010, says it's not so. The former dean of Harvard Law School says she was surprised "just how warm everybody is, how collegial." Kagan had to recuse herself from a third of the cases last year because of her previous work as solicitor general, the federal government's lawyer that represents the presiding administration's interests before the court. She is expected to play a larger role this term.

"If you're going to be somewhere a long time, it makes you appreciate congeniality," Kagan, 51, said in a video interview at the Aspen Institute.

The first call she got after her swearing-in ceremony was from Roberts.

"We're going to be serving together 25 years," the chief, 56, told her.

"Only 25?" Kagan replied.

Marsha Mercer is a freelance writer who covers public policy issues. She is based in Virginia.