(Abraham) Lincoln said he did not wage war on the Confederacy to stop slavery.
It takes two sides to make a war. The south was determined on a society based on slavery. The election of a Republican candidate showed that slavery might no be longer sufficiently protected by the government -- that it would no longer help them enough to "get their bread from the sweat of other men's faces," to use Lincoln's phrase.
They tried to bolt.
Lincoln, and the other loyal Union men were not going to let that happen. --They-- fought for the ideals of representative government. You just can't bolt when you don't like the outcome of an election.
The cause of the war was clearly slavery.
Walt
You're wrong. Slavery was an issue but it was not the only issue. I've already posted Lincoln's thoughts on the matter. He felt slavery would die, by itself. It (slavery) was not the issue revisionism would have us believe.
At issue was a) the North wanting to preserve the Union and b) the South wanting to preserve their sovereignty.