In a shocking incident that captured national attention, U.S. Representative Daniel Sickles murdered Philip Barton Key II, the U.S. Attorney General, in Washington, D.C. This act of violence stemmed from Sickles discovering that Key was having an affair with his wife, Teresa Sickles. Sickles confronted Key on the street and shot him three times, resulting in Key's death, which shocked both political circles and the public. The incident sparked a media frenzy, as it involved notable figures in government, delving into personal scandal amid the political climate of the time.

Daniel Sickles was a prominent politician known for his colorful personality and his involvement in various political endeavors. The murder took place in the 1850s, a period rife with political tension leading up to the Civil War. The trial that followed attracted significant media coverage and public interest, as Sickles claimed a defense of temporary insanity. This claim proved groundbreaking, as it was one of the earliest instances in which a defendant used insanity as a defense in a murder trial, leading to debates around mental health and criminal responsibility in the legal system.

Sickles was ultimately acquitted, which marked a turning point in how legal defenses were presented in courts. The case not only raised questions regarding the ethics of public figures but also had lasting implications on the judicial treatment of similar cases in the future. It became a point of reference in discussions on crime, morality, and the balance between emotional response and rationality in the eyes of the law.