Answer:
The Union could not continue with both free states and slave states.
Explanation:
Abraham Lincoln addressed "The House Divided Speech" in 1858. He emphasized that it was impossible for the North (also called the Union/the USA) to choose their state's own status. According to Lincoln, there will come a time that the Union will either become a fully-free state or a fully-slave state. It was impossible for it to continuously become divided in the long-run. His speech debated the goal of Stephen A. Douglas who supported "popular sovereignty" in which the settlers are given the option to choose between a free state or a slave state.