[Bull Snipe]

So whether or not its treason depends entirely upon the outcome on the battlefield.

Yes.

Union might destroyed the Confederacy. That fact is not invalid.

[FLT-bird]

Union might destroyed the Confederacy. That fact is not invalid. The outcome is not in doubt. The legality and morality of it very much is in doubt. Might does not make right.

[DiogenesLamp]

Union might destroyed the Confederacy. That fact is not invalid.

Criminals might murder innocents. That it is a fact has nothing to do with making it a moral thing to do.

Conquering and killing people who simply wanted independence was not moral.

Even after they slapped the "We did it because of slavery" bandage on it.