Peter Stephen du Ponceau (1760-1844) was a member of the Philadelphia Bar for nearly fifty years, during a period in which Americaís lawyers played an important part in fashioning the post-Revolutionary legal structure. Though contemporaries considered him to be an exceptional member of the legal profession on account of his command of history, his talent for learning languages, and most importantly, because of his scholarly knowledge of civil and foreign law (two legal areas little known to Americaís common law trained lawyers), he is largely ignored by historians of early American law. The best explanation for this oversight is his specialization in civil and foreign law, as most legal historians believe that, outside of early legal education, these areas of law contributed little or not at all to the formation of the American legal system. While the purpose of this thesis is to examine du Ponceauís contributions to the development of American law through his uncommon knowledge of civil and foreign law, this examination also suggests that these legal areas played greater roles in the origins of American law than previously thought.
Chapter one explores the first decades of du Ponceauís professional life in America and traces the path by which he gained recognition as a scholar of the aforementioned legal areas. The turbulent international relations with Europe that characterized the post-Revolutionary period generated a constant supply of cases pertaining to international, maritime, and commercial law. Du Ponceauís knowledge of foreign languages gave him access to important foreign legal sources, as well as to clients in need of his specialized legal skills. Though certainly benefitting from his unique position among his fellow lawyers, du Ponceau set aside time amidst his professional responsibilities to help fill what he recognized as a gap in American jurisprudential knowledge. Beginning around 1800, he promoted and contributed to the movement within the legal profession to translate important foreign and civil law works into English. He also made his specialized legal and historical knowledge available to U.S. political leaders.
Chapter two illustrates how du Ponceau utilized his legal expertise, as well as his many years of experience practicing law, in his opinions on and his participation in the legal reform movement in the 1820s to codify American law upon a civil law model. Although du Ponceau had worked hard during his early years in the bar to familiarize his fellow lawyers with this alternative legal system, in the end he argued against transforming the United States into a civil law country. In A Dissertation on the Nature and Extent of the Jurisdiction of the Courts of the United States (1824) he set forth his positions on American law, legal reform, and codification, and concluded that the U.S. possessed its own common law. This American common law not only was distinct from that of Englandís through its numerous alterations and improvements, but also was capable of resolving Americaís legal problems. The evolution of du Ponceauís ideas on American law emerged through earlier published writings and private correspondence, most notably through his letters to his eccentric and pro-codification friend, Irish lawyer William Sampson. Though he failed to persuade Sampson of the superiority of the common law method, he succeeded in convincing leading jurists on both sides of the Atlantic, including James Kent and Joseph Story in America and anti-codificationist lawyers in England.