The market economy was mostly influential in the institution of slavery by shaping the economy of the South. The South relied on cash crops as its main source of income. With the development of new technologies, plantations were able to grow, becoming so large that they required an enormous labor force in order to operate. This led to an increased interest in protecting slavery.
The Westward Expansion similarly affected the way slavery was seen in the country. First of all, as people acquired new territories in unexplored lands, they often wanted their slaves to accompany them, pushing the institution of slavery further west. Moreover, as new territories joined the nation, the new lands had to decide whether to become free states or slave states. This caused tension between the two separate areas of the country.