Link to the secession statements from Georgia, Mississippi, South Carolina and Texas. Useful reading when dealing with people who insist the war was not fought over slavery:
http://sunsite.utk.edu/civil-war/reasons.html
Money quote (from Texas):
"We hold as undeniable truths that the governments of the various States, and of the confederacy itself, were established exclusively by the white race, for themselves and their posterity; that the African race had no agency in their establishment; that they were rightfully held and regarded as an inferior and dependent race, and in that condition only could their existence in this country be rendered beneficial or tolerable.
That in this free government *all white men are and of right ought to be entitled to equal civil and political rights* [emphasis in the original]; that the servitude of the African race, as existing in these States, is mutually beneficial to both bond and free, and is abundantly authorized and justified by the experience of mankind, and the revealed will of the Almighty Creator, as recognized by all Christian nations; while the destruction of the existing relations between the two races, as advocated by our sectional enemies, would bring inevitable calamities upon both and desolation upon the fifteen slave-holding states."