Ta-Nahesi Coates recently highlighted a number of sources. http://www.theatlantic.com/politics/archive/2015/06/what-this-cruel-war-was-over/396482/ http://www.

Ta-Nahesi Coates recently highlighted a number of sources. http://www.theatlantic.com/politics/archive/2015/06/what-this-cruel-war-was-over/396482/ http://www.theatlantic.com/politics/archive/2015/06/what-thi... For extending slavery beyond the borders of south, see the quotes of Edward Pollard and Albert Gallatin Brown at the end of the post.