Which group uses violence and fear to achieve goals?

Terrorism, the calculated use of violence to create a general climate of fear in a population and thereby to bring about a particular political objective. Terrorism has been practiced by political organizations with both rightist and leftist objectives, by nationalistic and religious groups, by revolutionaries, and even by state institutions such as armies, intelligence services, and police.

A. southerners underestimated republicans eagerness to end slavery.