Bartleby, the Scrivener
Bartleby's resistance to follow orders from the narrator serves as an act of protest. Yet, Bartleby can't exactly be considered an activist. That is, his refusal to work is not for a bigger cause, but for his own personal gain.
The phrase "I prefer not to" grants Bartleby temporary power over the lawyer who cannot exert any authority over him. In doing so, he takes advantage of their system and chooses what he will and will not do.
Although his reign of power is short lived, he continues his protest until death. In this sense, Melville could be pointing at the ineffectiveness of a protest of inaction. However, in terms of power, Bartleby continues to do exactly what he says he will, placing him in more control than any character in the story.