The seccession Must not have been about Lincoln, because it happened before he took office.
Lincoln was elected November 6, 1860.
South Carolina seceded on December 20, 1860.
Lincoln's election was no more the cause for secession than slavery; merely the catalyst.
The Constitution, at that time, did not allow the United States Congress to interfere in the states' internal affairs, which included slavery.
The Declaration of Independence states "That whenever any Form of Government becomes destructive of these ends, it is the Right of the People to alter or to abolish it, and to institute new Government, laying its foundation on such principles and organizing its powers in such form, as to them shall seem most likely to effect their Safety and Happiness."