Question

Why did the Southern states secede?

Answer 1

Popular sovereignty: The Southern states felt limited as to the number of future slave states. More and more restrictions were being put on them and they saw their life style coming to an end.
States rights: were the states the supreme laws of the land or was it the federal government.
Trade: the South wanted free trade with countries that bought their cotton. The north wanted tariffs and taxes on many goods passing into and out of the country.
Slavery was being excluded in most western states and the south needed new land for cotton.

Answer 2

@Broskishelleh is correct

Answer 3

Yes @linda3