Recruitment of these regiments epitomized the "Brother's War" and the men serving in the two Union mounted infantry regiments were commonly referred to as "Home Yankees.
Intercine warfare is not and was not, even at the time of the Civil War anything new in the South-East. One things of Kings Mountain, where, I believe all the combatans except Ratrick Ferguson were Americans. I had relatives in the Legion (Dan Dockery) and some in East TN. Unionist partisan units. It was a brothers war in parts of that area for sure.