slavery and the Civil War

Over at History News Network is a new piece by Robert Cook, author of the recent Troubled Commemoration: The American Civil War Centennial, 1961-1965-- "150 Years after the Civil War, Can We finally Remember It the Way We Should?"

"Southern whites," Cook writes, "must be shown what they were not shown in the 1960s: That they seceded and fought primarily to protect slavery and defend the racial order that was based upon it."

Cook--and everyone else--needs to separate the two. Southern whites seceded to protect slavery; they fought for a variety of reasons. It's two different questions. We can see this in other wars (Vietnam, for example), that there is an obvious distinction between the reason for the war and the reason individuals fought in that war. Why do we have so much trouble understanding that for the Civil War?