I did not claim that every, or even most, individuals who fought in the war, did so over convictions about slavery. I said that slavery, as an institution, was the cause of the war. The Southern leaders seceded from the Union because they saw Abraham Lincoln, a moderate abolitionist, as plotting to end slavery across the nation. They were so afraid of his intentions toward slavery, that the Southern states refused to even put him on the ballot. The South was largely agrarian at the time, which was in contrast to the rapidly industrializing North, and to the people in power in the Southern States, the slave labor force was an important part of their economy. As for the assertion that the Southern states did not have representation or power within the Federal government in the years leading up the secession, this is completely untrue. The Southern states elected Congressmen, Senators and representatives, on a regular basis, just like the Northern states, and had all of the same voting rights and legislative authority.
If there is any doubt as to the motivations of the Southern leaders at the time, just read South Carolina's delcaration of secession:
http://avalon.law.yale.edu/19th_century/csa_scarsec.asp It is very clear that their main grievances were over the perceived threat to slavery. Here are a couple of choice quotes "For many years these laws were executed. But an increasing hostility on the part of the non-slaveholding States to the institution of slavery, has led to a disregard of their obligations, and the laws of the General Government have ceased to effect the objects of the Constitution" and as to their feelings on Lincoln "He is to be entrusted with the administration of the common Government, because he has declared that that "Government cannot endure permanently half slave, half free," and that the public mind must rest in the belief that slavery is in the course of ultimate extinction.".
And from the Mississippi declaration: "Our position is thoroughly identified with the institution of slavery-- the greatest material interest of the world." Alexander Stephens, Vice President of the CSA, further enumerated on slavery as the cause of secession, in his famous Cornerstone Speech, which I will let you Google for yourselves. This is not to demonize Confederates, because plenty of them were good people, and Robert E. Lee, was personally opposed to slavery. The individual soldiers probably did not care about slavery so much, but felt like they were righting for their states. Regardless, however, of whom was personally motivated for or against slavery, it is is clear that the Confederate leadership, at the time of secession, had slavery on their minds. It is also worth re-iterating that the Confederacy fired the first shots of the war; meaning the Union was not the aggressor side in the conflict.
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