The Acquittal of Daniel Sickles

February 19, 1859:

 Daniel E. Sickles, a New York Congressman, is acquitted of murder on grounds of temporary insanity. This is the 1st time this defense is successfully used in the United States. Sickles's career was replete with personal scandals. He was censured by the New York State Assembly for escorting a known prostitute, Fanny White, into its chambers. He also reportedly took her to England, leaving his pregnant wife at home, and presented White to Queen Victoria, using as her alias the surname of a New York political opponent. In 1859, in Lafayette Square, across the street from the White House, Sickles shot and killed the district attorney of the District of Columbia Philip Barton Key II, son of Francis Scott Key, whom Sickles had discovered was having an affair with his young wife.
Sickles was charged with murder. He secured several leading politicians as his defense attorneys, among them Edwin M. Stanton, later to become Secretary of War, and Chief Counsel James T. Brady, like Sickles a product of Tammany Hall. In a historic strategy, Sickles pled insanity—the first use of a temporary insanity defense in the United States.Before the jury, Stanton argued that Sickles had been driven insane by his wife's infidelity, and thus was out of his mind when he shot Key. The papers soon trumpeted that Sickles was a hero for saving all the ladies of Washington from this rogue named Key.
The graphic confession that Sickles had obtained from Teresa on Saturday proved pivotal. It was ruled inadmissible in court, but, leaked by Sickles to the press, was printed in the newspapers in full. The defense strategy ensured that the trial was the main topic of conversations in Washington for weeks, and the extensive coverage of national papers was sympathetic to Sickles. In the courtroom, the strategy brought drama, controversy, and, ultimately, an acquittal for Sickles.
Sickles then publicly forgave Teresa, and "withdrew" briefly from public life, although he did not resign from Congress. The public was apparently more outraged by Sickles' forgiveness and reconciliation with his wife, whom he had publicly branded a harlot and adulteress, than by the murder and his unorthodox acquittal.

See, they had trials of the Century before there was CourtTV.  Sex has sold for a long time.  And temporary insanity as a defense strategy has also been around for a while.