[Bull Snipe]

if by buying you mean onesies or twosies then tariff is probably not a problem. If you are going to buy 40 tons of iron rail and ship it North you will be required to pay the tariff because you are importing a tariffed product into the United States. No different than if you bought that 40 tons of rail in Birmingham England and had it shipped to New York. The principal in both situations is that the source is outside of the United States. After secession New Orleans in in a Foreign country.

[PeaRidge]

Nonsense. To get the goods, the New York merchant need only transfer them internally from Charleston, or up the Mississippi from New Orleans and so forth. Barring the logistically impossible establishment of custom houses at every road, railway, waterway, and river across the north-south border between Virginia and Arkansas, he could do so without paying a single tariff