After the British Indian War of 1812 America took some time off to just sort of feel good about itself for a while. Pretty much everyone thought this was a grand idea, except for some slaves who decided to be all difficult about it, what with the wanting to be free and all.
Suddenly the questions on everyone's mind were: "Where'd all these black people come from?" and "What are we going to do with them?" This is the point at which most history texts go backward in time a little and discuss slavery, so we guess we'll do that.
See, it turns out that there had been slavery in the New World since the first Spaniards landed. The Conquestadoors made many of the natives slaves in their never-ending search for El Dorado, which was a magical golden car. Then they started bringing slaves from African markets, because it was easier to keep someone subservient if they were in a foreign land where they didn't speak the language than if they were being held in their own country and knew the land better than the slave masters themselves. Also, the natives were dying off from of all the disgusting medieval diseases the Europeans brought with them. After all, it's hard to get anyone to work when he's dying of smallpox, no matter how hard you beat him. So, it was just easier to ship some slaves over from Africa.
When the British started settling in North America to grow tobacco, they had the same problems with the Native Americans that the Spaniards had. Since the British Navy had claimed most of the drunks and street urchins for themselves, the new settlers were faced with the choice of either importing some Africans, or getting their own hands dirty and doing a little work themselves.
Being English, they chose the first option.
And thus slavery came to America. And then the Revolution and all that other stuff kept everyone so busy that no one paid much mind to the slaves. Meanwhile, the new Americans kept bringing over new slaves by the shipload, because there was a lot of work to do in the Land of the Free.
By the early part of the 19th century, the slave trade had been abolished in Britain, with the exception of the Royal Navy, which could still impress people. They even went around capturing slave trading ships and fining the owners, which really impressed a lot of American sailors.
In eighteen-oh-something-or-other the Americans outlawed the import and export of slaves, but didn't outlaw slavery. Except in the northern states, where slavery had been abolished in the late 18th century.
Also in the late 17th century, Eli Watt invented a machine called a Cotton Spinning Jenny (which he apparently named after his daughter), that made it a lot easier to process wool. In reaction, the southern states stepped up their production of cotton in order to compete. Of course the southerners, like the English before them, weren't about to come down off their porches or carriages and do any work themselves, and they weren't about to pay anyone a decent wage for a day's work, so this really accelerated the slave trade. In fact, it made cotton so much cheaper to produce, that they put the sheep farmers right out of business. (They became so desperate that they even tried making clothes out of rabbit hair and llama fur.)
The Southern U.S. became insanely rich from all the free labor involved in the cotton trade. In fact, the whole South was so flush with cash that the owners of the big plantations decided to share the wealth - they completely eliminated poverty and built a model society which became the envy of the civilized world.
Oh, wait … that didn't happen. Instead they bought more slaves and land and politicians and lived like kings, while the slaves and the poor did all the work, had very little to eat, and received no education or public services. (It was like a Tea Party paradise down there.)
The North didn't care much for slavery, but they weren't particularly fond of Africans - after all, they had plenty of cheap, exploitable white labor coming in from Europe every day, so they didn't need slaves. Nevertheless, the whole slavery issue wasn't a big deal until it was time to make some new states, and a determination had to be made as to whether the new sates would be "slave" states or "free" states. The North didn't want to be outnumbered by the slave states, because a lot of Northerners wanted an end to slavery - some gradually, some immediately. The South didn't want their freedom (to own people) or rights (to deny rights to others) abridged in any way, so they felt that new states should all be "slave" states, or at the very least that the new states should be divided so as to keep the status quo. (There were eleven of each kind of state - "free" and "slave" by 1820, so it was all balanced out and everything.)
So when some of the miserable people just wast of the Missippi River wanted to form a state, but wanted to keep slaves (because most of the immigrants there had come from the South), there had to be a compromise. The new rule was that any new states from north of a certain line would have to be "free", while those to the south would be "slave" states, there would be an exception for the new state, as long as another new state could be formed in the north. The new Northern state was called Main, because it served one main purpose: to keep the states in balance. The new "southern" state was full of swamps and slaves, and was thus named "Misery" for the condition of the majority of its inhabitants.
This is NOT the last we'll hear about this whole slavery thing ...