Experts and Trials IV:  Why? 

 In my previous posts on this subject (see  here  for the most recent), I have explored our legal system's reliance on expert witnesses from game-theoretic and personal perspectives.  In this post, I take an entirely different approach, and ask the question: why is our system structured so? 

 The first question by many might be: what are the alternatives?  The traditional example is the French system, known as the Civil Law system (as opposed to the British-based Common Law system).  In France, a government judge acts as would the lawyers, judge, and jury in the American system.  This judge calls witnesses suggested by the parties (plus some others of his choosing), questions them himself, and then decides upon the proper course of action.  Trials often finish in one day; justice is summarily, if crudely, dispensed. 

 So why did these two systems develop differently, separated by less than 100 miles of the English Channel?  Though many answers surely exist in the historical literature, I offer one theory presented by Edward Glaeser and Andrei Shleifer, both in the Harvard Economics Department.  They place the roots of the two legal systems in the political circumstances in England and France in the 12th and 13th centuries, when the first characteristics of these procedures emerged. 

 The key element of a legal system, argue Glaeser and Shleifer, is its ability to limit the influence of corruption and coercion.  Viewed from this perspective, the strengths and weaknesses of juries versus government (then royal) judges become clear.  Juries, composed mostly of local commoners, would be subject to much coercion by local feudal lords.  Royal magistrates, on the other hand, would be far less susceptible to such forceful persuasion, but would be far more easily bribed by the king.  A country's choice between these two systems should depend on which problem is more dire: The threat of regional "bullies" or of royal domination. 

 Glaeser and Shleifer survey the historical record to argue that exactly this difference existed between England and France in the late middle ages.  England, recently conquered by and still under the rule of the Normans, had a much stronger monarchy, which imposed order on the countryside.  The smaller lords, with whom King John negotiated the Magna Carta, feared royal domination far more than they feared each other, and were willing to accept the possibility of local bias in juries so that the king would not interfere.  France, on the other hand, was far more violent, torn between many competing barons.  These dukes feared each other most of all, and knew that any jury would quickly fall under the sway of the local ruler; thus, they were willing to cede control of the legal system to the king. 

 I am not an historian, and so I cannot know whether these arguments accurately reflect the genesis of our legal system.  But even if the true explanation lies elsewhere, surely it will have the same historical feel.  These institutions have great inertia, and so it does not surprise me that factors so long ago have explanatory power.  Nonetheless, is this the best we can do?  Does our legal system reduce to an historical anachronism?