Philip Barton Key (April 5, 1818 – February 27, 1859)[1] was a United States Attorney for the District of Columbia.[2] He is most famous for having been shot and killed by the man whom he cuckolded, Daniel Sickles. Sickles defended himself by adopting a defense of temporary insanity, the first time the defense had been used in the United States.[2][3]
Born in Georgetown in Washington, D.C., Key was the son of Francis Scott Key[4][5] and the great-nephew of Philip Barton Key. He was also a nephew of Chief Justice Roger B. Taney.[4][5] He married Ellen Swan, the daughter of a Baltimore attorney, on November 18, 1845.[1] Allegedly the handsomest man in Washington[6] and by 1859 a widower with four children, Key was known to be flirtatious with many women.[7][8]
In 1859, Congressman Daniel Sickles shot and killed Phillip Barton Key, for having conducted a public affair with his wife Teresa Bagioli Sickles.[9] Some time in the spring of 1858, Teresa Sickles began an affair with Key.[2] Sickles had accused his much-younger wife several times during their five-year marriage of adultery, but she had repeatedly denied it to his satisfaction.[4] But then Sickles received an anonymous note on February 26, 1859, informing him of his wife's liaison with Key.[2][4] He confronted his wife, who confessed to the affair.[2] Sickles then made his wife write out her confession on paper.[10] Sickles saw Key sitting on a bench outside the Sickles home on February 27, 1859, signalling to Teresa, and confronted him.[2][4][10] Sickles rushed outside into Lafayette Square, cried "Key, you scoundrel, you have dishonored my home; you must die",[11] and with a pistol repeatedly shot the unarmed Key.[2][4] Key was taken into the nearby Benjamin Ogle Tayloe House, where he died some time later.[12]
Sickles was acquitted on the basis of temporary insanity, a crime of passion, in one of the most controversial trials of the 19th century.[13] Sickles' attorney, Edwin Stanton, later became the Secretary of War. Years later, while attending the theater in New York City, Sickles was aware of the presence of Key's son James Key in the audience, and both men kept watching each other throughout the performance. But nothing happened.[14]
At the time of his death, Key was the United States Attorney for the District of Columbia. He is buried in Oak Hill Cemetery in Washington and is also memorialized in a cenotaph in his son-in-law's family plot in Westminster Hall and Burying Ground in Baltimore, Maryland.