Answer:
The new western territories that were gradually incorporated into the United States since independence became over the years into a source of tensions between the north and south of the country, due to the status with which these new territories would enter the Union in relation to slavery.
Thus, the southern states sought for these new territories to enter as slave states, while the northern states sought the opposite. In any case, it was feared that there would be an imbalance in Congress regarding the representation of the slave and abolitionist states as a consequence of the entry of new states to the Union.
In this regard, various commitments and treaties were signed, seeking to maintain peace between both sides, the most important being the Compromise of 1820 and the Compromise of 1850. Finally, these tensions broke peace and triggered the Civil War.