About: http://webisa.webdatacommons.org/9743388

Property	Value
http://www.w3.org/1999/02/22-rdf-syntax-ns#type	http://www.w3.org/ns/prov#Entity
http://www.w3.org/ns/prov#value	So I think slavery is a headlining part of the financial and political oppression felt, not necessarily a separate reason if we accept your quote from Stephens as the widely accepted view in the South.
http://www.w3.org/ns/prov#wasQuotedFrom	economist.com