What was the catalyst for south carolina's secession from the union?

South Carolina left the union when Abraham Lincoln was elected US president, even though his name was not even on all of the ballots in the south. This made SC feel that they had no say in the election, and they were scared that Lincoln would abolish the slavery that was ever so crucial to their economy (though at the time he had no interest in doing that). So they made the decision to leave the union, and other states were relatively quick to follow.