Historians who address the origins of the American Civil War today agree that the preservation of slavery in the United States was the principal aim of the 11 Southern states (seven states before the onset of the war and four states after the onset) that declared their secession from the United States (the Union) and united to form the Confederate States of America (known as the "Confederacy"). However, while historians in the 21st century agree on the centrality of the conflict over slavery—it was not just "a cause" of the war but "the cause"—they disagree sharply on which aspects of this conflict (ideological, economic, political, or social) were most important, and on the North’s reasons for refusing to allow the Southern states to secede. Proponents of the pseudo-historical Lost Cause ideology have denied that slavery was the principal cause of the secession, a view that has been disproven by the overwhelming historical evidence against it, notably the seceding states' own secession documents.
What were the origins of the American Civil War?
Many historians agree that the issue of slavery was the main cause of the American Civil War.  A total of eleven southern states wanted to preserve slavery and as a result voted to secede from the United States.  These states subsequently declared themselves the Confederate States of America, also known as the Confederacy.  Also most historians agree that slavery was the cause of the war, they have differing views regarding which aspects (idealogical, economic, political, or social) were most important.  Their opinions also differ regarding the Northern States reasons for not allowing the Southern states to succeed from the Union.  Followers of an ideology known as the Lost Cause Idealogy have denied that slavery was the root cause of the war however this view has been disproven by overwhelming evidence, including the Southern states own secession documents.