Since the unnamed narrator of "The Black Cat" is writing from his prison cell, we can be sure that justice and judgment are on his mind. In the 1830s, when Poe was writing, the wheels of legal justice couldn't begin to turn until our narrator went too far and killed his wife. At the time, it wasn't illegal to abuse one's wife or animals. The story questions ideas of judgment and justice, and reflects the fraught and turbulent state of the US justice system in a time when rights for women, African Americans, animals, children, the mentally ill, and convicted murderers were hotly contested issues. Since domestic abuse happens every day, in spite of the law, "The Black Cat" still finds a receptive audience, over 160 years after it first appeared on the literary scene.
By making the narrator so unsympathetic that we can't feel sorry for him, "The Black Cat" makes an argument for the death penalty.
"The Black Cat" presents a complex argument against the death penalty, as will be demonstrated by examining the passages where hanging is discussed, and by drawing on arguments from the death penalty debate in Poe's time.