How did slavery intensify the states' rights issue during the early 1800's?

Answer 1

Just basic info -

The issue of states' rights means that the states can exercise the reserved powers of the constitution, that is, any power not given to the federal government or denied to the states is left to the states. Slavery, at that point, was not mentioned in the constitution. The slave states obviously wanted to keep slavery, and the other states wanted to ban the practice in the U.S. The argument was that, since the power to do so was not given to the federal government, then it must be a decision left to the states (ignoring, of course, the Commerce Clause). Anyway, the issue was intensified because of this argument.

Answer 2

States were being added during this period which impacted the balance of power in congress and the senate. New states could choose whether to allow slavery in their states or not. There were major battles over the issue in congress. Specifically Missouri and Texas.
Slavery proved no benefit when the war came. Slavery is a discentive to technological innovation, it is cheap labor. The north developed a powerful industrial and techonolgical base which inevitable crushed the simpler economy of the south.
The primary reason the Romans never developed a greater level of technology was that it depended on slavery for nearly everything. Without slavery Rome could have reached the moon in 300 AD, the basic technology had already been demonstrated by the greeks.

Answer 3

Slavery and states' rights became synonymous.

South = slavery = strong supporter of states exercising reserved rights as dictated under the 10th and, implicitly invoking, the 9th amendments.