How does it become a man to behave toward this American government to-day? I answer, that he cannot without disgrace be associated with it. I cannot for an instant recognize that political organization as my government which is the slave's government also.

If one were to tell me that this was a bad government because it taxed certain foreign commodities brought to its ports, it is most probable that I should not make an ado about it, for I can do without them. All machines have their friction; and possibly this does enough good to counterbalance the evil. At any rate, it is a great evil to make a stir about it. But when the friction comes to have its machine, and oppression and robbery are organized, I say, let us not have such a machine any longer. In other words, when a sixth of the population of a nation which has undertaken to be the refuge of liberty are slaves, and a whole country is unjustly overrun and conquered by a foreign army, and subjected to military law, I think that it is not too soon for honest men to rebel and revolutionize. What makes this duty the more urgent is the fact that the country so overrun is not our own, but ours is the invading army.

Can't get much more famous than "Civil Disobedience." The concept is pretty familiar to us in this day and age, and it's thanks to this humdinger of an essay by Henry David Thoreau. Martin Luther King, Jr. used it (the concept) to fight for the civil rights of African Americans, and it's been used in all other types of contexts to face up to political or social oppression.

Thoreau was in fact one of the first writers to clarify the idea of "civil disobedience." He's basically seen as the father of the concept. And in the above passage, we see him raising his kid in style—that is, elaborating on the notion, and in specific, how it relates to slavery.

Thoreau was a very active abolitionist. He didn't like slavery (which makes us like him more, of course). And he thought that the only way to fight slavery was to disobey the U.S. government, which at the time condoned and actively protected the institution of slavery.

Thoreau drives his argument home using logical deduction. Is it right that a government should enslave a part of its population? No. If it isn't right, then do we owe allegiance to that government, even if we're its citizens? No. It may seem obvious to us now, but back in the day Thoreau's ideas were pretty rebellious.

Like his Transcendentalist buddies, including Margaret Fuller, Thoreau was a big social reformer. He wasn't a guy who went along with the herd. Just because the government said that slavery was A-OK didn't make it morally right, he believed. And of course he was right. Good for him for being a free-thinking rebel.