In fact, the state rights defense of secession in 1860–1861 did not really appear in force until after 1865 as builders of the Lost Cause myth sought… - William C. Davis

Myths simply throw roadblocks in the path to enlightenment, and it is from truth that we have the most to learn. One man's truth, however, can be another's myth, and only through dispassionate and disinterested dissection of such stories can we tell the difference. The Confederate experience is dotted with episodes that are not particularly admirable.

Inextricably intertwined in the question was slavery, and it only became the more so in the years that followed. Socially and culturally the North and South were not much different. They prayed to the same deity, spoke the same language, shared the same ancestry, sang the same songs. National triumphs and catastrophes were shared by both. For all the myths they would create to the contrary, the only significant and defining difference between them was slavery, where it existed and where it did not, for by 1804 it had virtually ceased to exist north of Maryland. Slavery demarked not just their labor and economic situations, but power itself in the new republic.

Legalistic Southerners tried to view the Constitution as a contract. Unfortunately, that viewpoint breaks down when viewed as a lawyer views a contract. There are very few ways to legally break a contract unilaterally.