With all due respect for your attempt at civility, I am compelled to broaden your view of the War by a few facts to which you are apparently oblivious.
First, the vast majority of Southerners (94% as of the 1860 census) did not own slaves. To drink the Kool-Aid of the liberal media that these 94% would risk life and limb to defend the sins of the wealthy is to demonstrate extreme illogic and gullibility. This is excusable when you are in elementary school and have no experience with the deception of the media. To fail to acquire intellectual curiosity about such illogic is deplorable in an adult.
Second, Lincoln himself announced that he had no intention of interfering with slavery if he could preserve the union (read: Empire). He announced that the abolition or preservation of slavery had no influence on his pursuit of the war. He announced at his first inauguration that he had no intent to interfere with it.
Third, the Emancipation Proclamation freed absolutely no slaves. It specifically exempted the northern states and the portions of the South that were under military control of Federal forces. Lincoln himself remarked that it had absolutely no legal validity.
Fourth, Gen. Fremont, in charge of the military district of Missouri, declared all slaves in the district to be free only to have Lincoln castigate him for his pronouncement and force him to rescind his announcement. Lincoln repeated this action in the case of virtually every other Federal general who freed slaves, and he actually relieved at least one of command.
Fifth, the Federal government continued to employ slaves to build the Capitol and White House during the War. Does this seem a contradiction? Those slaves were not freed until years AFTER the War.
Sixth, General Grant allowed his wife to bring her slave into the Army camp during the War. Moreover, he is quoted as saying, "If I had any inkling that this war was being fought over slavery, I would throw down my sword and join the other side." He is also reported to have regretted the abolition of slavery and to have explained his opposition to this act with the words, "Good help is hard to find."
Seventh, (and I will stop here) when Lincoln was asked by his cabinet officers, "Why not simply let the South secede in peace?" Lincoln answered, "Where would I get the money to run the country?" You see, the South was providing at the time 85% of the Federal budget which was financed by tariffs which the north imposed on the South through the north's numerical superiority in Congress. The South, powerless to determine its own fate, had the choice of being compelled to continue with the unfair arrangement or to secede and go it on her own.
The north's inability to live under the provisions of the U.S. Constitution rendered the contract invalid. At the time, virtually everyone (on BOTH sides) knew secession to be legal. Forcing sovereign states to remain in the union at bayonet was a further violation of that contract. But the history books conveniently overlook these facts.