Final answer:
Southern secession was seen by secessionists as a legal right and an expression of self-government, but it was deemed illegal by the North and ultimately by the outcome of the Civil War, which affirmed the power of the national government and the illegality of secession. The correct option is A.
Step-by-step explanation:
Whether the Southern Secession was an example of self-government or a violation of self-government is a subject of historical debate. On one hand, the southern states believed in their legal right to secede, claiming the federal Constitution was a contract allowing for withdrawal if a state no longer consented to be governed federally. Jefferson Davis and other secessionists argued they were defending the liberty fought for in the Revolution and upheld the principle of states' rights.
However, most Northern politicians and President Lincoln saw secession as illegal, and the Civil War ultimately established the illegality of secession and reinforced the power of the national government. The post-war amendments and reintegration of the Confederate states solidified the position that states could not unilaterally secede.
This historical context suggests that while secessionists believed their actions were aligned with self-government, their defeat affirmed that such unilateral action was not recognized within the legal framework of the United States.