WASHINGTON — You can tell a lot about the Supreme Court by looking at who voted with whom. There are 36 possible pairs of justices, and in the term just concluded something interesting happened.
The top three spots were all taken by pairs of women. However you matched them up, Justices Ruth Bader Ginsburg, Sonia Sotomayor and Elena Kagan voted together at least 93 percent of the time.
The alignments are a product of ideology, not biology. “They are the three most liberal justices on the court, and it makes sense that they would often be in agreement,” said Pamela Harris, an adviser to the Supreme Court Institute at Georgetown’s law school.
The voting pattern highlighted the rightward drift of the fourth member of the court’s liberal wing, Justice Stephen G. Breyer, who broke from his usual allies in a series of important privacy cases.
In past years, it was often the conservative justices who voted together the most: Chief Justice John G. Roberts Jr. and Justice Samuel A. Alito Jr., say, or Justices Antonin Scalia and Clarence Thomas. This year, the right was more fractured. (The statistics come from Scotusblog, and the trends hold whether you look at all cases or just divided ones.)
The three female justices also dominated Supreme Court arguments in the last term. Justice Ginsburg asked the first question 37 percent of the time. Justice Sotomayor asked the most questions, averaging more than 21 in each hourlong argument.
Justice Kagan, a former dean of Harvard Law School and a former United States solicitor general, by many accounts asked the best questions of any of the justices. They were crisp and conversational and probed the heart of the case.
The spotlight often captured Justice Sotomayor this term, as her best-selling memoir gave rise to a book tour that drew adoring crowds. She was profiled on “60 Minutes,” talked with Oprah Winfrey and Jon Stewart, and visited “Sesame Street” and “The View.”
Lawyers who appear before her say she is a source of inspiration.
“I think she has come into her own and is establishing herself as a formidable and independent presence,” said Lisa S. Blatt, a lawyer with Arnold & Porter in Washington who has argued 33 cases before the court and served as a law clerk to Justice Ginsburg. “Like the other two women, she’s very comfortable up there, and that’s a great thing for a woman like me to see.”
Asked by e-mail for an assessment of Justice Sotomayor, a normally sober political scientist did not stint on her exclamation points.
“People love her!” wrote Lee Epstein, who teaches at the University of Southern California. “She made a lot of money!”
Justice Sotomayor’s financial disclosure forms show that she has received more than $3 million for the book.
Justice Ginsburg’s form for last year also contained an interesting disclosure. In November, she accepted an “award recipient gift bag” worth $2,500 — a swag bag, in the lingo — when she received Glamour magazine’s Woman of the Year Lifetime Achievement Award.
In their day jobs, the votes of the three justices are neither wholly predictable nor wholly united, said Lisa T. McElroy, a law professor at Drexel University.
“It’s important to note that the agreement was not on ‘women’s’ or ‘social justice’ issues,” she said.
The female justices were divided in two of the term’s biggest cases, Professor McElroy added. Justice Sotomayor wanted to provide an answer to whether there is a constitutional right to same-sex marriage, while the other two women said the court was powerless to decide the question in the context of a challenge to California’s ban on the practice.
Justices Ginsburg and Sotomayor also split on affirmative action, with Justice Ginsburg filing the lone dissent in a case that sent a challenge to the University of Texas’s affirmative action plan back to the lower courts for a second look under a more demanding standard. (Justice Kagan, who worked on the case as solicitor general, recused herself.)
Still, said Erwin Chemerinsky, the dean of the law school at University of California, Irvine, “they are the three most liberal justices on the court, and so it is not surprising given their ideological similarity that they vote together the most.”
Justice Breyer, the next most liberal justice, voted with conservative justices in a decision allowing the police to take DNA samples from arrestees and in dissents from rulings limiting the use of police dogs to sniff for drugs outside homes and warrantless blood testing of people stopped for drunken driving.
In all three cases, he and Justice Scalia traded places, with Justice Scalia joining the three women in pressing for broad Fourth Amendment protections.
“I ought to be the pinup of the criminal defense bar,” Justice Scalia told an audience at the University of Wyoming in October. He had been hunting in Wyoming, with Justice Kagan.
Justice Scalia described their trip in an interview in February with Nina Totenberg at George Washington University.
“It was, unfortunately, not successful,” he said. “We got antelope tags, which are expensive for out of state, and mule deer tags. Didn’t get a single shot at an antelope or a mule deer. So she ended up killing a white-tailed doe, which she could have done in my driveway.”
“She dropped that doe with one shot,” he said of Justice Kagan’s exercise of her Second Amendment rights. “Boom. Just like that.”
Justice Scalia is also close to Justice Ginsburg, but there are limits to their friendship. “I can’t imagine Ruth hunting,” he said.