The concept of a 'people's war,' first described by Clausewitz in his classic treatise "On War", was the closest example of a mass guerrilla movement in the 19th century. In general during the American Civil War, this type of irregular warfare was conducted in the hinterland of the border states (Missouri, Arkansas, Tennessee, Kentucky, and northwestern &lt;a href="West%20Virginia%20in%20the%20Civil%20War"&gt;Virginia / West Virginia&lt;/a&gt;). It was marked by a vicious quality of neighbors fighting each other as other grudges got settled. It was frequent for residents of one part of a single county to take up arms against their counterparts in the rest of the vicinity. Bushwhacking, murder, assault, and terrorism were characteristics of this kind of fighting. Few participants wore uniforms or were formally mustered into the actual armies. In many cases, civilians fought against civilians or civilians fought against opposing enemy troops.