I seem to remember the pact that both South Carolina and Alabama made prior to the War. That was if one of the two states left the Union then the other would follow, hence the lyrics to the Bonnie Blue flag, "1st came South Carolina who boldy took the stand and then came Alabama who took her by the hand" Even though Alabama was NOT the second state to leave she had already made her promise to South Carolina and kept it.
As many folks know the people in South Carolina did NOT have a chance to vote for President in 1860. True the people of SC did elect the legislators and they cast the states vote for President. If memory serves me correctly I think there were 16 legislators for the state of SC in 1860. (In many states such as Georgia where their was a popular vote for President, Lincoln's name did NOT appear on the ballot) (One could argue that the Republican Party was fairly new and had NO right to be on the ballot) These 16 men of SC were the same men who added President Lincoln's name to the states ballot and who threatened to leave the Union if Lincoln did win the general election. It may be possible that these 16 men had something to gain for their votes and actions? Some people feel that these 16 men did get their wish and brought War to the country. I'm NOT sure I agree with that view but it is interesting to ponder. Many people of the South needless to say had low opinions of Lincoln, just look at the election results from his native born state Kentucky in either the 1860 or 64 election results. Something like 4%