Question

In the early and mid-1800s, sectionalism was strongest

Answer 1

1. If my memory serves me well, in the early and mid-1800's, sectionalism was strongest in the South, where people felt their economy depended on slavery. After the invention of the cotton there were very high demand for slave labor and slavery become the necessary part of agricultural output in the South. 

2. I am definitely sure that, Henry Clay’s American System, which was established in the early 1800's, placed tariffs on foreign imports to build roads and infrastructure. The main goal of Henry Clay's American System was to support the domestic economy of the United States.

3. As far as I remember, South Carolina eventually repealed its Ordinance of Nullification in exchange for the federal elimination of the Tariff of 1828 and a gradual reduction on import taxes over a decade.

4. The best description of the nullification is: the idea that a state could refuse to follow a federal law it disagreed with. That means, the state has the right to nullify any federal law if they see it unconstitutional.