That is the only explaination that embodies all the facts. It is the only answer that makes sence. It is the only answer that says that our forefathers were not just stupid, blind, ingorant, hayseeds that followed after the elite class of society.
The war was in fact the northern Morality (Preserve the Union/free the slaves) vs southern Legality (the Constitution/Supreme Court).
The real question is, "Is the use of a Gun (War) the way we want to change laws?" Or was there a better way?