Expert Answer: More states: more opportunities for slavery to spread, which was supported by many, but many also feared the idea of mor slave states being added.
While driven by economic ambitions and a sense that the United States was “destined” to span the entire continent, the war also raised the issue of how acquisition of such a large territory would affect the balance between slave and free states. The congressional response—the Great Compromise of 1850—not only allowed for the possible creation of new slave states, but also placed legal demands upon northerners to aid in the recapture of fugitive slaves.
