The best answer is bleeding Kansas.
Bleeding Kansas was the name given to a series of violent confrontations in Kansas, and the neighboring border towns of Missouri, following the passing of the 1854 Kansa - Nebraska Act. The conflicts between Anti - slavery and Pro - slavery militant activists from 1854 - 1861 that reached a state of low intensity civil war.
The border war known as Bleeding Kansas was a crucial point that led to the road of the American civil war of 1861 - 1865. The outbreak of the violent event in Kansas came during the presidency of Franklin Pierce,
