While in recent decades the Court has become more diverse in some areas, such as gender and race, presidents have also appointed Justices with increasingly uniform educational and professional backgrounds. This lack of professional and educational diversity may be sub-optimal. Adrian Vermeule, for example, offers a carefully-reasoned argument for having at least one Justice with training in another discipline (he suggests appointing a Justice with a PhD in economics). At its most extreme, Vermeule’s argument insists that the professionally-diverse Justice have no training in law, to correct for correlated biases held by lawyer Justices.
My research suggests, however, that the extreme step of eliminating formal legal training will introduce a particular bias which some will find objectionable. In the past, Justices who did not attend law school were significantly more politically predictable than Justices who shared the benefit of formal legal education. Today, of course, a president choosing a Justice who did not attend law school would likely select a person who also has expertise in another field. But it is not clear a Justice with an advanced degree in economics or another discipline would exhibit the same political restraint as a Justice who went to law school. It seems more likely that Justices who attend law school will be either better-equipped or more inclined than others to vote independently of their personal political views. This may be reflected in greater levels of judicial restraint, incremental decision-making, and application of doctrines such as stare decisis.