50 years ago I was taught in my HS American History class (in Monroe, WA) that slavery was NOT the primary cause of the civil war. We weren't told about this:


"Our new government is founded upon exactly the opposite idea; 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. This, our new government, is the first, in the history of the world, based upon this great physical, philosophical, and moral truth."


Alexander H. Stephens 
Vice President of the Confederate States of America
Savannah, Georgia
March 21, 1861


Full text @ http://teachingamericanhistory.org/library/document/cornerstone-speech/