Answer:
The acquisition of new territories was a determining factor that motivated the beginning of tensions between the northern and southern states in the era prior to the Civil War. This was so because the entry of new states into the nation supposed the generation of a disorder in the balance of power between the slave states and the abolitionist states, with which both groups faced each other to determine the state of the new territories regarding of slavery.
As a result of these political tensions, several agreements were signed between the north and south of the country, such as the Missouri Compromise or the Compromise of 1850, until finally the Civil War broke out in 1861.