Oh, fuck, Dean. You had to start a history discussion. At least it isn't another discussion about the Constitution. 
War is always complicated. There is never one reason to go to war. Lincoln was not a stupid man by any stretch. He would not have viewed war as an option if slavery or even state's rights were the only issues on the table. You, Min and a few others have outlined every issue that was at hand fairly well. However, I would like to add that the cultures of the North and South were very different. However subtle the forces are, cultures that are that different will always find reasons for fighting. Now, I am not getting into details, but merely talking about human nature. The southerners were different than northerners and vice versa. They were finding reasons to piss each other off for decades before the war began. That kind of nonsense always escalates, enters into politics and then becomes war, without proper resolution. There could be no proper resolution. The idea of a part of the south separating from the union was as old as the union itself. It had to come to a head and it did.
Oh, and the British, Canadians and Indians weren't giving the rabblerousers of 19th century United States enough to bitch about anymore. They needed something to slake their thirst.

War is always complicated. There is never one reason to go to war. Lincoln was not a stupid man by any stretch. He would not have viewed war as an option if slavery or even state's rights were the only issues on the table. You, Min and a few others have outlined every issue that was at hand fairly well. However, I would like to add that the cultures of the North and South were very different. However subtle the forces are, cultures that are that different will always find reasons for fighting. Now, I am not getting into details, but merely talking about human nature. The southerners were different than northerners and vice versa. They were finding reasons to piss each other off for decades before the war began. That kind of nonsense always escalates, enters into politics and then becomes war, without proper resolution. There could be no proper resolution. The idea of a part of the south separating from the union was as old as the union itself. It had to come to a head and it did.
Oh, and the British, Canadians and Indians weren't giving the rabblerousers of 19th century United States enough to bitch about anymore. They needed something to slake their thirst.