“We don’t really take a case in order to, quote-unquote, do justice” or “to make sure that the good guy won and the bad guy lost,” Scalia said.

Robert Bork provides a popular answer: justices “tend to drift to the left in response to elite opinion.” According to his theory, judges come to associate with and respond to “the intellectual class . . . dominant in, for example, the universities, the media, church bureaucracies, and foundation staffs.” Once seated on the court, right-leaning judges eventually adopt “the intelligentsia’s attitude, which is to the cultural left of the American people.”

As the left-leaning judge Guido Calabresi explains, “I am extraordinarily role-conscious. I think that we play roles all the time. What is appropriate for me as a judge, what is appropriate for me as a scholar, what is appropriate as a dean [of Yale Law School], and what is appropriate if I did more op-ed writing . . . are completely different things.”

But more is at work than the desire to convey an appearance of objectivity. The job of judging, unlike most occupations, strongly encourages individuals to see sides of an issue that are otherwise easily ignored. And the information that emerges may help explain why juridical drift is so often leftward.

Justice O’Connor, in a tribute to the late Justice Thurgood Marshall, described the influence of his “special perspective” on her—an influence that appears to have contributed to her leftward trajectory: “At oral arguments and conference meetings, in opinions and dissents, Justice Marshall imparted not only his legal acumen but also his life experiences, constantly pushing and prodding us to respond not only to the persuasiveness of legal argument but also to the power of moral truth.”

When Theodore Roosevelt, feeling badly betrayed by his erstwhile nominee, remarked of Justice Oliver Wendell Holmes Jr. that he “could carve out of a banana a judge with more backbone than that”. . .