Of course it was all about slavery. That’s why it took three years and a presidential re-election campaign for Lincoln to declare the slaves (only those in the South) free.

The fact that the Confederacy WAS fighting primarily in defense of slavery is not at all logically incompatible with the fact that the Union WAS NOT fighting primarily to end it. It is perfectly possible for both clauses of my first sentence to be true.

Lincoln was, of course, not a radical abolitionist; but if you go back and look at Southerners’ words, especially around 1860-61, most of them clearly thought that he was.

Some more quotes on the pro-slavery motivations of Confederates:

“Our position is thoroughly identified with the institution of slavery– the greatest material interest of the world. Its labor supplies the product which constitutes by far the largest and most important portions of commerce of the earth. These products are peculiar to the climate verging on the tropical regions, and by an imperious law of nature, none but the black race can bear exposure to the tropical sun. These products have become necessities of the world, and a blow at slavery is a blow at commerce and civilization. That blow has been long aimed at the institution, and was at the point of reaching its consummation. There was no choice left us but submission to the mandates of abolition, or a dissolution of the Union, whose principles had been subverted to work out our ruin.” – Mississippi’s Declaration of Causes for Secession

“The Government is to be with the North…There must inevitably be a want of sympathy between that Government and the South…The party which has the supremacy is not only sectional and geographical, but it is based upon opinions which will subvert, if unresisted, the foundations  of the social structure of the fifteen southern States. Its fundamental idea is hostility to the South and her peculiar property, and it arrays the eighteen northern against the fifteen southern States of the confederacy….Abolitionism has triumphed…The vox populi which created and must uphold Lincoln’s administration will still have the mastery, and require obedience, and compel the support of northern interests, the development of northern ideas, the security of northern power, and the destruction of African slavery.

The institution of slavery is put under the ban, proscribed, outlawed. Southern States and citizens of those states, because of the possession of slave property, are stigmatized and pilloried and reduced to inferiority…The progress of anti-slaveryism, with its gigantic and God-defying assumptions, may well awaken serious apprehensions…The animating principle of the [Republican] party is hostility to slavery. It champions the idea of the natural, inherent, inalienable right of the Africans to freedom, and to the rights, privileges, and immunities of citizenship. It wages an unceasing crusade against our civilization….When [the Republicans] speak of ‘equality’ and ‘freedom’ and ‘liberty,’ they mean the equality and freedom of southern slaves…” – Congressman Jabez Curry (Alabama), 1860

“If emancipation be brought about as will undoubtedly be the case, unless the encroachments of the fanatical majorities of the North are resisted now, the slaveholders, in the main, will escape the degrading equality which must result, by emigration, for which they would have the means, by disposing of their personal chattels; whilst the non-slaveholders, without their resources, would be compelled to remain and endure the degradation. This is a startling consideration. ..What would be the case in many o four States, where every other inhabitant is a negro, or in many of our communities…where there are twenty to one hundred negroes to each white inhabitant? Low as would this class of people sink by emancipation in idleness, superstition and vice, the white man compelled to live among them, would by the power exerted over him, sink even lower, unless as is to be supposed he would prefer to suffer death instead.” – Leading Southern intellectual/writer James De Bow, 1860

“….So deep…was this anti-slavery planted in their [the Republicans’] hearts that they forgot and forgave all asperities of the past, the political differences of the present, and regardless of the almost certain defeat which the future had in store for them, cordially embraced each other in the bonds of anti-slavery hatred, preferring defeat under the banner of abolition to success, if it had to be purchased by a recognition of the constitutional rights of the South….There is one dogma of this party which has been so solemnly enunciated, both by their national conventions and Mr. Lincoln that it is worthy of serious consideration. I allude to the doctrine of negro equality…Mr. Lincoln and his party assert that this doctrine of equality applies to the negro, and necessarily that there can exist no such thing as property in our equals. Upon this point both Mr. Lincoln and his party have spoken with a distinctness that admits of no question or equivocation. If they are right, the institution of slavery as it exists in the Southern States is in direct violation of the fundamental principles of our Government….

With the exception of a few dull speeches in favor of a protective tariff, intended for circulation in Pennsylvania and New Jersey, and still fewer number of pitiful appeals for squandering the public lands, the whole canvass was conducted by the most bitter and malignant appeals to the anti-slavery sentiment of the North. Under the sanction of Senators and Representatives in Congress the country was flooded with pamphlets and speeches holding up slave-holders as “barbarians, more criminal than murderers,” and declaring unhesitatingly in favor of immediate and unconditional abolition in every State in the Confederacy where it now exists — doctrines which are the necessary and legitimate consequences of the universally recognized dogmas of the Black Republican party….Hostility to slavery is the magic word which holds [the Republicans] together; and when torn to pieces by other dissensions, hatred to the South and her institutions swallows up all other troubles and restores harmony to their distracted ranks. ” – Congressman Howell Cobb (GA), 1860

“You are not satisfied that we of the South are almost reduced to the condition of overseers of northern capitalists. You are not satisfied with all this; but you must wage a relentless crusade against our rights and institutions. And now you tender us the inhuman alternative of unconditional submission to Republican rule on abolition principles, and ultimately to free negro equality and a Government of mongrels or a war of races on the one hand, or on the other secession and a bloody and desolation civil war, waged in an attempt by the federal government to reduce us to submission to these wrongs. It was the misfortune of Mexico and Central and South America, that they attempted to establish governments of mongrels, to enfranchise Indians and free negroes with all the rights of freemen, and invest them, so far as their numbers went, with the control of those governments…Our own Government succeeded because none but the white race, who are capable of self-government, were enfranchised with the rights of freemen. The irrepressible conflict propounded by abolitionism has produced now its legitimate fruits — disunion. Free negro equality, which is its ultimate object, would make us re-enact the scenes of revolution and anarchy we have so long witnessed and deplored in the American Government to the South of us.” – Congressman John H. Reagan (TX), 1861

“….The real cause of the intense excitement of the South, is not vain dreams of national glory in a separate confederacy…is the profound conviction that the Constitution, in its relations to slavery, has been virtually repealed; that the Government has assumed a new and dangerous attitude upon this subject; that we have, in short, new terms of union submitted to our acceptance or rejection. Here lies the evil. The election of Lincoln, when properly interpreted, is nothing more nor less than a proposition to the South to consent to a Government, fundamentally differing upon the question of slavery, from that which our fathers established. If this point can be made out, secession becomes not only a right, but a bounded duty.…The Southern man, politically, is the slaveholder; the Northern man, politically, is the non-slaveholder. The rights of the South are the rights of the South as slaveholding; the rights of the North are the rights of the North as non-slaveholding. This is what makes the real difference betwixt the two sections. To exclude slaveholding is, therefore, to exclude the South.” -Presbyterian Rev. James Henry Thornwell of SC, 1861

“We have dissolved the late Union chiefly because of the negro quarrel.”  – Robert H. Smith of Alabama, “An Address to the Citizens of Alabama, on the Constitution and Laws of the Confederate States of America,” delivered on March 30th, 1861
“[T]he new [Confederate] Constitution has put to rest forever the agitating question relating to our peculiar institutions — African slavery as it exists among us ] — the proper status of the negro in our form of civilization. This was the immediate cause of the late rupture and present revolution. Jefferson, in his forecast, had anticipated this, as the ‘rock upon which the old Union would split.’ He was right. What was conjecture with him, is now a realized fact. But whether he fully comprehended the great truth upon which that rock stood and stands, may be doubted. The prevailing ideas entertained by him and most of the leading statesmen at the time of the formation of the old Constitution were, that the enslavement of the African was in violation of the laws of nature; that it was wrong in principle, socially, morally, and politically…Those ideas, however, were fundamentally wrong.

They rested upon the assumption of the equality of the races. This was an error. It was a sandy foundation, and the idea of a Government built upon it — when the storm cam and wind blew, it fell. Our new Government is founded upon exactly the opposite idea; its foundations are laid, its cornerstone rests, upon the greath truth that the negro is not equal to the white man; that slavery, subordination to the superior race, is his natural and moral condition. This, our new Government, is the first in the history of the world, based upon this great physical, philosophical, and moral truth….[The Confederate government] is the first Government ever instituted upon principles in strict conformity to nature, and the ordination of Providence, in furnishing the material of human society…. Our system commits no such violation of nature’s laws. The negro by nature, or by the curse against Canaan, is fitted for that condition which he occupies in our system.

The architect, in the construction of buildings, lays the foundations with the proper material — granite — then comes the brick or marble. The substratum of our society is made of the material fitted by nature for it, and by experience we know that it is the best, not only for the superior but for the inferior race, that it should be so. It is, indeed, in conformity with the Creator. It is not for us to inquire into the wisdom of His ordinances or to question them. For His own purposes He has made one race to differ from another, as He has made ‘one star to differ from another in glory.’ …The great objects of humanity are best attained, when conformed to his laws and degrees, in the formation of Government as well as in all things else. Our Confederacy is founded upon principles in strict conformity with these laws. This stone which was rejected by the first builders ‘is to become the chief stone of the corner’ in our new edifice…” – Confederate VP Alexander Stephens, March, 1861