If John Roberts is confirmed as the next chief justice, he will inherit a Supreme Court sharply divided on America’s toughest issues. But there is one question of national importance on which the judges will easily agree: Harvard or Yale? If Cantab pride has anything to do with it, the judges will side with Harvard in a 6-1 decision.

For a school that lays claim to the last three presidents and the country’s top-ranked law program, Yale has produced relatively few Supreme Court justices. Clarence Thomas, its single representative, serves alongside five Harvard alumni, with a potential sixth, Roberts, on the way. Though some attribute Harvard’s dominance of the Court to simple talent or luck, other experts suggest that it illustrates the differences between the sizes, histories and philosophies of Yale and Harvard Law schools.

Elena Kagan, dean of Harvard Law School, said its five alumni on the court — Antonin Scalia, Anthony M. Kennedy, David Souter, Stephen Breyer, and Ruth Bader Ginsberg — are striking examples of the quality of Harvard students and their commitment to public service.

“We’re conducting a friendly takeover of the place,” Kagan said. “I’m going for nine.”

Yale Law School professors and students are quick to point out reasons other than student quality for why Cantabs outnumber Elis. Size, they agreed, is the major factor. With about 1,890 students, Harvard Law is three times larger than Yale, graduating three times as many potential Supreme Court Justices each year. That alone, combined with the element of luck, explains much of the discrepancy, they said.

But exactly to what degree size contributes remains open to debate.

Yale professor and historian Gaddis Smith said Yale Law School’s history also had a hand in the Supreme Court’s current composition. While Harvard Law has enjoyed its reputation as one of the nation’s premiere institutions since its founding in 1817, Yale Law did not become a major player until the 1930s. Smith said Yale’s reputation for excellence exceeded Harvard’s only about 20 years ago, after the current Supreme Court justices graduated.

“Harvard’s reputation was way ahead of Yale’s as the big, powerful, good school for ambitious people,” he said.

Yale’s original status as a runt also forced it to adopt an alternative teaching philosophy, said Robert Gordon, a legal history professor at Yale and a Harvard Law School graduate. As it struggled to compete with Harvard in early 20th century, Yale Law established a niche in public policy, encouraging its graduates to work in public interest law and other fields apart from corporate and criminal law. The decision gave birth to the “legal realism” movement of the 1930s, in which law was viewed as less of a science and more connected to public service, Dean of Yale Law School Harold Koh said.

Gordon suggested that Yale’s philosophy may have resulted in its relatively low number of Supreme Court appointments compared to Harvard. Presidents, particularly Republicans, he said, have historically nominated judges with long paper trails and mainstream careers as corporate lawyers or prosecutors.

“When people are looking for federal judges, they’re looking for people who are safe, sound and reliable,” Gordon said. “These are criteria that favor people who have chosen conventional careers in the law.”

He added that Yale nevertheless has an excellent record of staffing federal judgeships. Two names frequently mentioned to replace retiring Justice Sandra Day O’Connor — U.S. Appeals Court judges J. Harvie Wilkinson III ’67 and Samuel Alito Jr. LAW ’75 — are Yale graduates.

Gordon also said Harvard’s political leaning, which is slightly more conservative than Yale’s, could make its graduates more likely to be nominated by Republican administrations, as were three of the five sitting Harvard Law alumni. On the other hand, Clarence Thomas, Yale’s sole representative, was nominated by Republican President George Bush in 1991.

Kagan dismissed the notion that differences in philosophy or ideology could have given Harvard an advantage over Yale, saying that Harvard students are too diverse to be classified under particular interests or political views. Rather than attesting to a focus on corporate law — as Gordon suggested — Kagan said Harvard’s success on the Supreme Court demonstrates its concern with public policy.

“The judiciary is public service, and the number Harvard has in the judiciary is emblematic of its commitment to public service activities,” she said.

A final reason for Yale’s weaker showing on the court, some professors suggested, may be the most rudimentary job qualification: connections. With Harvard’s large size comes a powerful “old boys’ network,” as Gordon called it, in which former classmates and professors give each other a leg up.

Harvard faculty, Smith said, have been a particularly useful asset.

“Harvard for many years had a faculty tradition of being closer to government — people taking leaves and virtually commuting between Cambridge and Washington,” he said.

Smith noted that one of the most important connections in Harvard’s web was Felix Frankfurter, a famous professor, government recruiter and Supreme Court Justice in the 1940s and 50s.

But Cantabs in need of a Supreme Court justice’s recommendation should be careful who they call. Ruth Bader Ginsberg actually got her diploma from Columbia Law School. Harvard, which she attended with fewer than a dozen other women, refused to let her finish her third year in New York while her ailing husband received medical treatment there. Kagan has since apologized to Ginsberg on behalf of the institution.

Because Ginsberg did not technically receive her degree at Harvard, only four Harvard Law School graduates currently sit on the court. That’s still three more than Yale, but Elis said they are untroubled.

“We should want to have good justices without regard to what law school they go to,” Koh said. “I don’t view this issue as part of a Harvard-Yale game.”

Jessica Anderson LAW ’06 agreed that the Supreme Court is not a point of school pride, but said stacking it with judges from the same school is a dangerous tactic.

“Having people who came up into the law with the same intellectual approach limits the view that the court takes on law,” she said.

Her Harvard friends, however, do not see it that way.

“They would always ask, tongue-in-cheek, “‘How many justices do you have on the Supreme Court?'” she recalled.