Edwin M. Stanton could be a pill. Irritable, sarcastic and often completely unreasonable, no doubt many of the Union Generals who had to deal with him often thought that they were dealing with a very mad man. Mad in an emotional sense Stanton often was, anger often seeming to be the prime emotion he displayed throughout his career, at least after the death of his beloved first wife in 1844 which had a souring impact on his disposition. However, he was also a very able man, and that compensated for his complete lack of tact in dealing with virtually everyone he came into contact with. Prior to becoming Secretary of War he had been one of the ablest attorneys in the country. Doubtless his most famous, or rather infamous case, was in the defense of future Union general Daniel Sickles.
Sickles in 1859 was a Democrat Congressman from New York, already notorious for having been censured for bringing a prostitute into the New York General Assembly chamber. Leaving his pregnant wife at home, on a trip to England he had introduced the same prostitute, Fanny White, to Queen Victoria under an alias, the surname of which was that of a political opponent in New York. Sickles obviously viewed his vow of marital fidelity with complete contempt. However he did not view the vow of fidelity given to him by his wife Teresa in the same light. When he found out on February 26, 1859 that his long-suffering wife was carrying on an affair with the United States Attorney for the District of Columbia, Philip Barton Key II, the son of Francis Scott Key, the composer of the Star Spangled Banner, he murdered Key the next day in Lafayette Park across from the White House, shooting him through the heart. Sickles immediately surrendered to the Attorney General who lived just a few blocks away.
His trial was one of the most sensational in American history. Public opinion was almost totally on his side, painting Sickles as an outraged husband defending his wife Teresa from a villain who had seduced her. Sickles engaged a stellar defense team which included Stanton. The defense team had a problem. No matter what the public thought as to his motivation, Sickles was manifestly guilty. Stanton hit upon the idea of raising the novel defense of temporary insanity which had never before been successful in the United States. This was a true stroke of legal genius. It allowed the defense to put on endless lurid testimony as to the affair and, in effect, have the dead man tried rather than Sickles. In his closing argument Stanton portrayed the ever adulterous Sickles as a defender of marriage: