Answer:
The shift toward a national market economy and the factory system in the United States led to increased sectional tensions and political divisions primarily due to:
Economic Disparities: As the North industrialized and the South remained agrarian, economic differences widened.
Divergent Interests: The North favored protective tariffs and opposed slavery, while the South saw tariffs as harmful and defended slavery.
Slavery Conflict: The factory system in the North clashed with the South's reliance on slavery.
Representation Disputes: Growing Northern population raised questions about political representation.
States' Rights: Differences in interpretation of states' rights intensified sectional divides.
These factors fueled political parties aligned with sectional interests and ultimately contributed to the outbreak of the American Civil War.