We’re not fighting for slaves.
Most of us never owned slaves and never expect to,
It takes money to buy a slave and we’re most of us poor,
But we won’t lie down and let the North walk over us
About slaves or anything else.
We don’t know how it started
But they’ve invaded us now and we’re bound to fight
Till every last damn Yankee goes home and quits.
Stephen Vincent Benet, John Brown’s Body
I certainly agree with video above from Prager University that the Civil War was started over slavery. As Jefferson Davis stated in his initial address to the Confederate Congress:
In the meantime, under the mild and genial climate of the Southern States and the increasing care and attention for the wellbeing and comfort of the laboring class, dictated alike by interest and humanity, the African slaves had augmented in number from about 600,000, at the date of the adoption of the constitutional compact, to upward of 4,000,000. In moral and social condition they had been elevated from brutal savages into docile, intelligent, and civilized agricultural laborers, and supplied not only with bodily comforts but with careful religious instruction. Under the supervision of a superior race their labor had been so directed as not only to allow a gradual and marked amelioration of their own condition, but to convert hundreds of thousands of square miles of the wilderness into cultivated lands covered with a prosperous people; towns and cities had sprung into existence, and had rapidly increased in wealth and population under the social system of the South; the white population of the Southern slaveholding States had augmented from about 1,250,000 at the date of the adoption of the Constitution to more than 8,500,000 in 1860; and the productions of the South in cotton, rice, sugar, and tobacco, for the full development and continuance of which the labor of African slaves was and is indispensable, had swollen to an amount which formed nearly three-fourths of the exports of the whole United States and had become absolutely necessary to the wants of civilized man. With interests of such overwhelming magnitude imperiled, the people of the Southern States were driven by the conduct of the North to the adoption of some course of action to avert the danger with which they were openly menaced. With this view the legislatures of the several States invited the people to select delegates to conventions to be held for the purpose of determining for themselves what measures were best adapted to meet so alarming a crisis in their history. Here it may be proper to observe that from a period as early as 1798 there had existed in all of the States of the Union a party almost uninterruptedly in the majority based upon the creed that each State was, in the last resort, the sole judge as well of its wrongs as of the mode and measure of redress. Indeed, it is obvious that under the law of nations this principle is an axiom as applied to the relations of independent sovereign States, such as those which had united themselves under the constitutional compact. The Democratic party of the United States repeated, in its successful canvass in 1856, the declaration made in numerous previous political contests, that it would “faithfully abide by and uphold the principles laid down in the Kentucky and Virginia resolutions of 1798, and in the report of Mr. Madison to the Virginia Legislature in 1799; and that it adopts those principles as constituting one of the main foundations of its political creed.” The principles thus emphatically announced embrace that to which I have already adverted – the right of each State to judge of and redress the wrongs of which it complains. These principles were maintained by overwhelming majorities of the people of all the States of the Union at different elections, especially in the elections of Mr. Jefferson in 1805, Mr. Madison in 1809, and Mr. Pierce in 1852. In the exercise of a right so ancient, so well established, and so necessary for self-preservation, the people of the Confederate States, in their conventions, determined that the wrongs which they had suffered and the evils with which they were menaced required that they should revoke the delegation of powers to the Federal Government which they had ratified in their several conventions. They consequently passed ordinances resuming all their rights as sovereign and Independent States and dissolved their connection with the other States of the Union.
However, it is one thing to say that the War started over slavery and another to say that every Union soldier was fighting to end slavery and every Confederate soldier to preserve it. As the passage from Stephen Vincent Benet’s epic poem on the Civil War, John Brown’s Body, indicates, there existed various motivations for the soldiers in the ranks. Robert E. Lee noted at the end of the War that rather than fighting to preserve slavery, he rejoiced that the War ended it, and we have no reason to doubt his statement. Slavery was the spark that caused the War, but once it started the issues of Union and independence for the Confederacy were key motivations to fight. Lincoln, while hating slavery, indicated on several occasions that his primary goal was the preservation of the Union. Jefferson Davis, ever the defender of slavery, by the end of the War was willing to give it up if that was the price that must be paid for the Confederacy to win its independence.