Answer:
It would allow slavery to spread north of the line established by the Missouri Compromise.
Explanation:
In Stephen Arnold Douglas bid to divide regions of Nebraska and Kansas to invalidate the Missouri Compromise line, he proposed to divide the Nebraska Territory in two. However, some northerners objected to such action. The reason behind the objection is that the then northern part of the United States was generally anti-slavery and it is believed that such action would allow slavery to spread north of the line established by the Missouri Compromise.
