Question

what agrument did southerners give in support of slave labor

Answer 1

The basic one was you'll take better care off what you own then what you rent as the northern industrialist do by paying employees. This was somewhat true at the time if you consider job safety and pay.

Answer 2

Absolutely true, KenLJW. Also they argued there was no other way to structure society between African slaves and the white population of the South. Recall that the abolitionists existed mainly where few if any slaves did. Recall also that while many Southerners deplored the slave system from a moral standpoint, they accepted it as the only viable social structure for the time being. The idea of social control was marked in the white Confederacy.