Significance: Pinkney's most significant contributions were made through his advocacy before the Supreme Court. He demonstrated a genius for argumentation and a commitment to constitutional government.
Pinkney, who aspired to be a physician, entered the study of law through the invitation of Samuel Chase. In the 1780's Pinkney developed his legal and political career in Maryland; he opposed ratification of the U.S. Constitution and, in 1789, called for the abolition of slavery. Pinkney became involved in the national government and accepted George Washington's appointment in 1796 to pursue U.S. claims against Britain based on Jay's Treaty (1794). Pinkney developed expertise in admiralty law and served as a negotiator during the next three presidential administrations. Pinkney was a flamboyant yet elegant court advocate. Though seriously wounded during the War of 1812 while serving as James Madison's attorney general, Pinkney recovered and entered the Senate, where he remained until his death. It was during this period that Pinkney secured his reputation as a gifted and persuasive advocate before the Supreme Court. His most meaningful cases were McCulloch v. Maryland (1819), in which he provided direction for the Missouri Compromise of 1820, and Cohens v. Virginia (1821), in which he argued in defense of states’ rights and for the constitutionality of the Bank of the United States.