The main cause of the Civil War was States Rights. The South was afraid that Abraham Lincoln would emancipate slaves, and they believed that the US President should not be making decisions that affected the entire country and that States should have the right to make those decisions. It wasn't so much the emancipation of slaves that concerned the South, but rather the fact that if Lincoln were to free the slaves, it would be denying the states their rights.
In order to fully understand the reasoning of the South, you have to step into their shoes. Back then the US was thought of much as we think of the UN, a group of nations (or states) that were united. So if several leading nations in the UN were to tell us to do something that we thought was infringing on our rights, what would we do?
On the other side of the argument, the Northern states saw is as an uprising, or rebellion, against the US, and were determined to keep the Union together. If it meant war, so be it. Lincoln summed it up when he said, "A house divided against itself cannot stand." The North believed that if the South seceded that both nations would collapse. The economy was very dependent on both the agriculture of the South and the factories of the North. If the South had won the war, there might have been an economical collapse.
Of course there is many other reasons contributing to the friction felt between the US and CS, and there will always be debating about the cause of the war, but most agree that the reason stated above is the main, underlying issue.
The Division Over Slavery
It is, of course, the fact that slavery was an integral part of the Southern agricultural economy made it a more important "right" than other activities that the states did not want to cede to the federal government. Some historians describe the Civil War as the triumph of industry over agriculture, which when comparing the two economies is also a reasonable factor. And slavery was the biggest single attribute that differentiated the North and South. To say that the war's single biggest cause was not slavery is to overlook the contentious history of the early 19th century, in which slavery was a principal issue.
The South fought for the preservation of slavery. The narrative that the South fought for "states rights" is a part of the "Lost Cause" narrative as explained in historian Gary W. Gallagher's book The Myth of the Lost Cause and Civil War History.
The fact that slavery was an integral part of the cessation of many states can be found in many of the state's declarations of cessation.
An example can be found in Mississippi's declaration with the quote "Our position is thoroughly identified with the institution of slavery".
The confederate constitution has a clause that enshrined slavery into the law, Article I Section 9(4).
The final example would be the speech given by the Vice President of the Confederacy Alexander Stephens in which he spoke about the founding of the confederate government saying "its foundations are laid, its corner-stone rests upon the great truth that the negro is not equal to the white man; that slavery—subordination to the superior race—is his natural and normal condition."
The North's, Lincoln's primary objective was not to free enslaved people but to keep the Union together.
In a letter written by Lincoln to Horace Greeley he is quoted saying ""If I could save the Union without freeing any slave I would do it, and if I could save it by freeing all the slaves I would do it; and if I could save it by freeing some and leaving others alone I would also do that.".
After Lincoln won, many Southern leaders felt that disunion was their only option, fearing that the loss of representation would hamper their ability to promote pro-slavery acts and policies according to historian William W. Freehling,.
In the end, while slavery was not the only reason for the war, it was the most prominent, other reasons include protectionism, sectionalism and a territorial dispute.
I encourage anyone who reads this to do more research into the causes of the Civil War and use this answer and other answers here as a starting point.
The Civil War
The Confederate South.
It was the south against the north. The Union (North), The confederates (South).
US Civil War=North wanted to retain the South Vietnam War=North wanted to conquer the South
In the American civil war, yes.
The original reason for the North to fight the Civil War was to prevent the South from seceding.
because they were fighting over money but north didn't actually want to fight
Acually it was the north versus the south. The north wanted no slaves and the south did.