Civil war happened due to the increasing strife between North and South USA over economic and cultural divide.
The government of the USA was dominated y the North as the south was less populous and because the North was more urbanized.
For a long time, there were laws and sanctions that profited north at the expense of the south including tarries on cotton production and other such laws which were detrimental to the south.
Unrest was also at its peak because of abolitionist sentiment in the north where a huge portion was actively trying to free the slaves from the south.
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