Whether the state was a slave state or a free state.
Explanation:
This was the main concern of the United States when it came to accepting a new state to the Union. This was because of the delicate balance of power that existed in the country. The strong opposition of slave states to free states (and viceversa) led to an equal number of slave and free states in the Union in order to maintain a balance of power. The admission of a new state threatened such a balance.
