At Civil War Talk, a correspondent posted the following:
In general Southerners seem to have had a greater connection to their state than Northerners did. I have never been sure of why that was (it seems to have been roughly similar at the time of the Revolution), but it is clear that it was so. Perhaps Northerners were less likely to feel that way because of the greater amount of immigration in their area, the easier transportation network, etc.
I responded as follows:
David Potter makes a point that is relevant here, although it tends away from your argument. Potter argues that loyalty to locality and loyalty to a larger political entity (nationalism) are not necessarily contradictory values. Often, there is no conflict between the two, and one can be loyal to and supportive of both. There is no need to prioritize one's values.
Sometimes, however, the loyalties come into conflict. In those cases, one must draw priorities. This is not necessarily an all-or-nothing exercise. One may feel loyalty to one's country, but feel more loyalty to one's locality or state.
Potter argues that in this respect there was nothing unique about the South. Back during the War of 1812, it was New England that perceived tensions between loyalties. The national government was taking actions that were perceived to be harmful to the section. New England rumbled with discontent. James Madison and Henry Clay -- and John Calhoun! -- were the nationalists, because they saw no conflict of loyalties.
The War of 1812 abated of course. Later on, southerners began to perceive (rightly or wrongly -- we can avoid that issue) that the national government was moving in a direction that threatened their interests. They began to have to prioritize their loyalties. By then, it was the Northerners (or most of them) who perceived no contradiction between their loyalties to their section and their country as a whole. Daniel Webster was able to speak "as a Union man" because he saw no conflict between that role and the interests of his state and section.
On a more practical level, it's worth remembering that the south was deeply tied into national and international commerce. Planters -- including those hotspurs in South Carolina -- marketed an international cash commodity. They had agents and brokers in Britain and shippers in New York. Even most farmers produced a bale or two as a cash crop. I just don't think the isolated south vs. engaged north holds up.
I think the dynamic was the other way around. Perceived national threats to local interests generated increasingly strident defenses of local interests, and the elaboration of theories designed to reduce national power. On the other hand (and I think this also supports my contention), where an increase in federal power was perceived to benefit the south (fugitive slave law, federal slave code in the territories), southerners readily embraced those propositions and indeed maintained that they were constitutionally required.
The same goes for the north, by the way. Where northerners perceived a conflict between national and local, and had to prioritize their loyalties, many went local. Examples would include the personal liberty laws designed to hamper the Fugitive Slave Act, and court decisions such as Abelman v. Booth, which held the Fugitive Slave Act unconstitutional.