This novel was published after the abolishment of slavery in America, but it takes place when the Civil War was still decades away and slavery was still practiced in Missouri. In many ways, the novel reflects the lack of national consensus on the issue of slavery by portraying dishonorable white people like Tom and honorable Black people like Chambers. Twain readily acknowledges that slavery steals a man's freedom and causes people to commit desperate acts, but juxtaposes this with the character who has every advantage yet still chooses to behave despicably: Tom.

Skin color, however, is an untrustworthy marker of identity. Roxy could easily pass for white, and Tom and Chambers actually switch identities and races. Given all of the advantages of wealth and whiteness, Tom is a despicable character, while Chambers, consigned to slavery, is loyal and forgiving. What Roxy does is unforgivable, but it is also driven by love and fear of a dismal future for her child. Twain seems to be making the argument that race is a superficial, and ultimately useless, identifier. Every person has attributes and flaws, regardless of the color of their skin.