How does southerners politicians support seceding from the union?

Essentially, the South wanted States' rights and their right to property (slaves). They feared that overrepresentation of the North, combined with pro-abolition legislation would lead to the South losing these rights. As stated in the excerpt, the South wanted to leave the Union before they were forced out or their rights were taken away.

Hope this helps!

The repetition of initial consonant sounds is called alliteration