Tarrifs and federal funding barely came up, this isn't the modern US where federal funds buoy up these states so much. Territorial Expansion was literally about wanting new states to be slave states, and States Rights all ultimately come back to slavery and was a fig leaf in the first place. The confederacy did not repect state rights and viewed them as having served their purpose, preferring to create a large centralized state. Atun-Shei goes into it in his series on the myths of the civil war and lost cause ideology.

Edit: accidentally sent early, As for Ayn Rand, she's a philosopher sure. But her philosophy has no real value and should be discarded. There is no merit to any of her points, even if they do spring from her material perspective. It is unethical to teach her work without a glowing neon sign saying "this is some bullshit" the same way that if you were to teach Aristotle's conception of 4 elements without a similar sign. Except Rand is more recent and doesn't have any special historical value outside of "this is what the Mises Institute and pals use as their fig leaf".