What was the north point of view on slavery by the 1850s

The united states constitution gives the the power to regulate interstate commerce.

Which best describes the purpose of the south carolina exposition and protest, which was written by john c. calhoun? a) to explain why the south was nullifying the tariff of 1828 b) to describe the ways the tariff of 1828 would southerners c) to persuade northern states to rebel against the federal government d) to ask england for if the south decided to secede from the union

What important race leader of the early twentieth century is being described?