Why do you need history to be a lawyer?

History is important for the study of law because studying history teaches one to look for cause and effect relationships.  In order to fully appreciate an action, one must look at the reasons why the action took place.  This ability to analyze is important for both historians and lawyers.  Historians are also excellent writers who carefully check facts and are comfortable citing outside sources.  Lawyers have to write well in order to have influence and they cite precedents to make their arguments even stronger.  
 
Also, much of history, especially political and legal history is the study of laws.  The Constitution is the supreme law of the United States.  Lawyers base their defenses and prosecutions on whether or not someone's constitutional rights were violated.  The more one can study the Constitution, the more likely one is to know his/her rights and can better exercise them.