Sorry, Sgt. Major, but I must disagree with you on this one. The idea that the south was fighting for states' rights is in fact the southern "spin" on the war. The only states right endangered was the extension of slavery. The south wanted every new state to be allowed to choose whether to be free or slave, knowing that if they were not allowed to extend slavery, the free states would sooner or later have the power to pass what became the Thirteenth Amendment. They knew Lincoln and the Republicans would pass legislation preventing the spread of slavery, and once the 1860 election results were in, they began seceding.
Lincoln, at first, did not want to use slavery as an issue for fear of losing the border states Maryland, Kentucky and Missouri. But by mid-1862, he realized he had to broaden the scope of the war. It was becoming obvious that reunion was not enough. In, I believe, October of '62, he issued the Emancipation Proclamation, which took effect Jan. 1, 1863, and from there the north was fighting for both reunion and the end of slavery.
The south has never admitted they were fighting for slavery and how could they? But they did and it's simply a hard fact.
