Walter Smith Cox was a professor of law at what was then called Columbian University, known today as The George Washington University, in Washington, D.C.. On February 26, 1879, Cox was nominated by President Rutherford B. Hayes to a new seat on the United States District Court for the District of Columbia created by 20 Stat. 320. He was confirmed by the United States Senate on March 1, 1879, and received his commission the same day. During his service, he presided over the trial of Charles J. Guiteau, the assassin of President James A. Garfield. Cox retired from the federal bench on July
Charles J. Guiteau lined up every day to see them in person were continually rejected, as were his numerous letters. By the early days of Garfield's administration, Guiteau was living in Washington, D.C., destitute and forced to sneak from rooming house to rooming house without paying for his lodging and meals, and to walk around the cold, snowy city in a threadbare suit, without a coat, hat or boots. He spent his days in hotel lobbies reading discarded newspapers to keep track of the schedules of Garfield and his cabinet and making use of the hotels' complimentary stationery to write them letters pressing