Final answer:
Seven southern states seceded from the Union before Lincoln was inaugurated. Their secession was primarily driven by the fear that Lincoln's election would threaten slavery. By seceding early, these states sought to protect their states' rights and the institution of slavery.
Step-by-step explanation:
Seven states - South Carolina, Alabama, Florida, Georgia, Louisiana, Mississippi, and Texas - seceded from the Union before Abraham Lincoln was inaugurated as President. The primary reason for their secession was the fear that Lincoln's election would threaten the institution of slavery. These states believed that they had the legal right to secede in order to protect their states' rights and the institution of slavery. By seceding before Lincoln could enact any policies, these states were taking preemptive action to safeguard their interests