What was the role of slavery in early American history? Was it justified?

In early American history, slavery was used as a means of keeping certain groups of society underneath those in power as subservient, obedient, free laborers. Similar tactics were also used in American society as a means to remind women, particularly those who wanted to be independent and find honest work on their own, of their proper place underneath white men. In the 1800s, both women and African-Americans were seen as lesser than white men, both intellectually and socially.  In fact, it was often the most impoverished or socially stigmatized women who were the most independent of their gender. For example, in the novel "Work: A Story of Experience," we witness the main character, Christie, engaging with women who are both independent and socially conscious.  It is from these “working” women that she learns her abolitionist ideals, just as author Louisa May Alcott did.
By creating this social stigma surrounding women who earned their own keep, those in power were able to keep women in their traditionally subservient role. At the beginning of Chapter 3, Christie attempts to assert her independence by claiming that she will "not be a slave to anybody.” Even the humiliating examination that she is subjected to as a woman attempting to become an actress parallels the examinations that slaves undertook before being bought. This shows that Alcott understood the use of humiliation as a tactic to keep slaves and women in their subservient roles and expressed empathy for those on the receiving end of that treatment.
Louisa May Alcott believed that the lawful slavery of human beings, both as black people and as women, was a travesty. For this reason, she chose to associate herself with working women and to write stories on their behalf. In "Work," she clearly demonstrates a belief that nothing could be less justifiable; women like Christie, and indeed all human beings, deserve to be independent and allowed to control the outcome of their own lives. Using groups of people for free labor, although advantageous at times, was certainly not something that could be justified, especially if you believed, as Alcott did, that human beings were equal regardless of their skin color.