I'd imagine that support for protectionism would be higher in the Midwest and in the South while opposition to it would be higher in the Northeast and in the West
Are you sure about the South being more protectionist? The South has always been very hostile to trade unionism, so I don't know if the South would be very supportive of protectionism. The Jacksonian Upper South/Appalachian regions sure, but the core such as AR, TX,LA,FL, MS, GA,AL,SC,NC/VA,TN, would be free trade supporters.
Though perhaps an exception, I believe both of Alabama's Senators at the time may have voted against NAFTA; even one would have been a bit of an outlier in the South. I believe as well that among Reagan's few decisions to increase tariff protections were multiple cases in which tariffs were increased on textiles which are big in, among other states, Strom Thurmond's South Carolina.
Alabama also has a much higher unionization rate than its surrounding Southern states, and disproportionately so:
Could this have had an effect in the NAFTA vote?
>TFW New York has the highest unionization in the country
