Slavery is economic suicide.
Slaves were not paid and had no money, so they cannot become part of the economy. Since the slaves, which made up a large amount of the population in the South, could not buy the products made from the raw materials produced, the economy was dropping. If one studies the economy closely before the Civil War period, one may see that the economy was on a spiral downward, and on the brink of a depression that could destroy the Nation. Slavery is a terrible drain on resources and the economy. The North was only preserving our Nation by purging the South from it's own destruction.