Slave labor is the only effectual, and therefore cheapest, labor which the Southern States can use in the production of their staples. Experience, in the South, has shown this to be true in the building of railroads. Slave labor must be used successfully on uniform work, requiring physical strength, without judgment or discretion. Wherever such work in large quantity can be found in the Southern climate, slave labor is the cheapest that can be applied. –Thomas R. R. Cobb, 1858 Which argument for slavery does this passage support? Slavery is beneficial to enslaved persons. Slavery has been practiced throughout history. Slavery has been accepted by many civilizations. Slavery is the cheapest way to grow labor-intensive crops.