To what extent did the election of Abraham Lincoln as president cause the outbreak of the U.S. Civil War?

The election
of Abraham Lincoln did cause the outbreak of the Civil War, but only in the immediate sense.  To
think of what this means, think of a person who smokes, is terribly obese, and never exercises. 
The person goes out for a walk and has a heart attack.  Did the walk cause the heart attack?  In
a sense, it did, but the heart attack was really caused by all of the things that had gone
before.  Lincolns election was the same way.

Lincolns election was the
relatively immediate...