"If one considers the citizens of the Confederate States to have remained Americans, then one is forced to admit that the so-called War Between the States was in fact a civil war between Americans."
Although Canadians don't consider themselves Americans, the live on the North American Continient, Mexico too.
With you statement that all living on the continent are Americans, does that imply that the War with Mexico was a Civil War? I don't thnk you meant it to be so.
The point is the Southern States seceeded, creating a new Nation, the War for Southern Independence couldn't have been a Civil War by definition.
As you say, "you can't have it both ways", is true. But because the Federal Government welcomed the secession States back into their fold, they recognized all soldiers who took the oath as American Soldiers. Tragically this left my GGG Grandpa A.C. McKay a Confederate soldier out of the mix until all the scars were healed and consequently he was dead. He never took the oath of allegiance.
Deo Perpetua!!!!!