As I noted here, if Elena Kagan's Supreme Court nomination is confirmed, we poor oppressed Protestants will be shut out of the institution that we used to overwhelmingly dominate.
Just as Kagan's presence on the Court would mean that only two religions would be represented (Roman Catholicism and Judaism), it would also be true that only two law schools (Harvard and Yale) would have produced almost all of the nine justices.
The one exception, Ruth Bader Ginsburg, who received her law degree from Columbia, had earlier attended Harvard Law School. So it is true, as noted in this National Public Radio report, that all of the nine (after a Kagan confirmation) would have been students at either Harvard Law or Yale Law.
NPR mentions certain highly-rated law schools further west, that have, up until recently, been represented on the Court. John Paul Stevens, whose retirement led to Kagan's appointment, is an alumnus of Northwestern Law School. Two recently-departed justices, the late William Rehnquist and Sandra Day O'Connor, went to law school at Stanford.
But, aside from that, there have been some justices in recent decades who attended law schools that did not sit particularly high in the ratings. Chief Justice Warren Burger got his law degree from what was then called St. Paul College of Law, later renamed William Mitchell College of Law. Thurgood Marshall graduated from Howard University Law School, and Hugo Black from the University of Alabama Law School.
During the first two years of the Burger Court, the Harvard/Yale group was in the minority (William Brennan and Harry Blackmun from Harvard, and Potter Stewart and Byron White from Yale). But William O. Douglas, a Columbia Law alumnus, made for an overall Ivy League majority.
Is there any correlation between the party of the president who nominated a justice, and which law school that justice attended? No. Including Kagan, and counting Ginsburg with the Harvard bunch, the five Republican appointees include three from Harvard and two from Yale. The four Democratic appointees include three from Harvard and one from Yale.