Westward Expansion<span> and the American </span>Civil War<span>. To many nineteenth century Americans, the </span>expansion<span> of slavery into Western territories caused a great deal of controversy. ... These fears were realized when the </span>expansion<span> of slavery into western territories entered Congressional debates.</span>
Answer:
D. the Student Nonviolent Coordinating Committee
Sorry if I got this wrong, if I did. Please tell me out on my bluff!