Pro-slavery advocates before the American Civil War used the legal argument that the US Constitution allowed slavery, and argued, too, that subsequent actions, such as the Fugitive Slave Act and the Dred Scott decision, reinforced the legal concept that slaves were, first and foremost, items of property in the eyes of the law. As for religious arguments, the pro-slavery groups used the sanction of slavery in the New Testament in such verses as Ephesians 6:5 and Colossians 3:22 (advising slaves to obey their masters) to argue for a right to slavery. Morally, the pro-slavery forces moved from the idea of slavery as a necessary evil to the more radical idea of slavery as a positive good, arguing that slaves got cradle-to-grave security and were better treated than Northern factory workers. Economically, they asserted that the agrarian Southern economy would collapse without a cheap, reliable labor force such as slavery guaranteed.
The abolitionists, often led by Quakers and freed slaves such as Frederick Douglass, argued against the legality of slavery, calling this a mistake, and asserting that as humans, Black slaves were endowed with the same natural rights of freedom and the pursuit of happiness that white people enjoyed. On religious and moral grounds, abolitionists often cited the biblical golden rule of "doing unto others as you would have they do unto you" as an argument against slavery. Since no free person was offering to trade places with a slave, abolitionists saw this as evidence that slavery was a cruel and unnatural state. Abolitionist writers such as Harriet Beecher Stowe used the moral examples of slaves who fell into both "average" and heinous situations to show the vulnerability of the slaves and the abuse that could run rampant even in "good" households. Economically, some abolitionists argued for reparations to owners for freeing slaves, such as was done in England to recompense English owners of slaves in colonial territories after they were freed, while others pushed the argument that an economy that necessarily relied on slavery deserved to collapse.
Ultimately, both moral and economic tides ran against slavery, and the Civil War brought it to a legal end.