[XRdsRev]

As an aside, taking this issue one step further, could treason and legitimate rebellion have existed at the same time within the Southern secession movement ? For example, it could be argued that that members of Southern legislatures and militias from states that had legitimately voted to secede using proper political means were engaged in a rebellion seeking to divest themselves and their state from ties to the Federal government.

Whereas members of legislatures and militias from states like Maryland, Kentucky and Missouri who served in the Confederate forces, were from states that never seceded from the Union were possibly guilty of treason because they not only sought to dissolve their state's association with the Federal Government but to overthrow the legally elected (pro Union) governments in their respective states including the Federal representatives of such.

[JohnGalt]

That is an excellent point, and if you had a chance to read Thomas Flemings "When This Cruel War Is Over" (2000, NY Times Best-seller) you got a glimpse of blatant (by legal definition) treason running up to officers in the Union army who had trouble fighting for the butchers of the North.

War is the destroyer of civil society and throwing around legalese to explain this or that is so unappealing.