Final answer:
The election of Abraham Lincoln, who opposed the spread of slavery into the territories.
Step-by-step explanation:
The immediate cause of the secession of several Southern states from the Union was the election of Abraham Lincoln. Lincoln, as a Republican candidate, opposed the spread of slavery into the territories. This led to the belief that the Southern way of life and their economic system based on slavery would be under threat, prompting states such as South Carolina, Mississippi, Florida, Alabama, Georgia, Louisiana, and Texas to secede from the Union.
Learn more about Secession of Southern states