I think Elena Kagan will be an outstanding Justice, not just because of her outstanding (and underrated) technical abilities—as I'll mention shortly, I think the Court as a group is already well-stocked, if anything overstocked, with technical legal skills—but because she possesses that rarest of qualities, the charisma of leadership.  This is now a Court with two natural leaders—Kagan and Roberts—and the fascinating question will be whether the building is large enough to contain two outsize talents of the same type.

Stepping back from Kagan, I'm struck by the narrow bandwith of the debate over her qualifications.  The political system has converged to a point at which all the Justices attended either Harvard or Yale, and the only question is whether all nine of the Justices should be former lower-court federal judges—in effect that was the Republican position —or whether it's acceptable to have one Justice who, like Kagan, has never served as a judge.  Those positions are shockingly narrow, on at least three dimensions.  First, not all good lawyers attended either Harvard or Yale, heretical though that claim might seem; the opposition to Harriet Meiers was pervaded by the snobbery of the elite bar, who sneered at her credentials.  Second, many great Justices had no previous service as federal appellate judges; given that the Court decides many cases that involve high politics, one might think that having at least a few Justices who served in elected office or in the upper reaches of the executive branch might usefully diversify the Court's base of experience and information.  Third, and most radically, I believe there is a good case that the Court should contain at least a few non-lawyers.  Let me expand on that last point, which is outside the mainstream, but which is supported by a growing body of academic work on the determinants of good collective decision making.

No legal rule requires that appointees to the Court be lawyers, in the sense of possessing a J.D. degree and being a member of a state bar association.  The Court's docket, roughly speaking, consists of two types of cases—"autarkic" cases in which the legal issues are strictly technical and internal to law, and "non-autarkic" cases in which the right legal answer itself depends upon the answer to questions about which lawyers have no specialized technical ability or comparative advantage.  Examples in the latter category include the questions about the effect of climate change debated in Massachusetts v. EPA, a case from a few years ago, or the questions about the nature and consequences of military detention that the Court has debated in several cases after 9/11.  In the non-autarkic cases, a group consisting solely of lawyers is likely to be at sea; a group containing at least one member with relevant non-legal expertise is likely to make better decisions.  The illusion that drives the debates over qualifications for Justices is that the Court does only technical lawyers' work.  Although that is more often true for lower federal appellate courts, a great deal of the Court's docket involves questions of fact, causation or policy in various specialized nonlegal fields or else involves matters of high politics, as to which legal training is essentially irrelevant.  Ironically, then, the insistence that all or nearly all Justices should have been lower federal judges selects for technical legal skills, precisely the dimension on which the work of the Court differs from the work of the lower federal courts.