Writer, thinker, transcendentalist, and neckbeard enthusiast, Henry David Thoreau published his essay, "Civil Disobedience" in 1849. It basically argued that governments do messed up stuff way too often, and that individuals should follow their own moral conscience instead of going along with unjust laws, wars, and customs.

Thoreau saw slavery for the nightmare and abomination it was, and also railed against the beginnings of what he considered American imperialism, which at the time was epitomized for Thoreau by the Mexican-American War.

There are many nuggets of wisdom, controversy, and 19th century New England wit in the essay. But there is at least one argument that made its way directly into Dr. King's "Letter from Birmingham Jail": we shouldn't have respect for law just because it's the law.

I think that we should be men first, and subjects afterward. It is not desirable to cultivate a respect for the law, so much as for the right. […] Law never made men a whit more just; and, by means of their respect for it, even the well-disposed are daily made the agents of injustice. (Source)

Not included in "Civil Disobedience": Thoreau's passionate argument in favor of neckbeards.