During this pre-Civil War era, why was adding land so problematic for the United
States?

United States - Secession and the politics of the Civil War, 1860–65: In the South, Lincoln’s election was taken as the signal for secession, and on December 20 South Carolina became the first state to withdraw from the Union. Promptly the other states of the lower South followed

Explanation:

monopolies  came to the united states with the colonial administration. the large-scale public works needed to make the new world hospitable to old world immigrants required large companies to carry them out. these companies were granted exclusive contracts for these works by the colonial administrators. even after the american revolution, many of these colonial holdovers still functioned due to the contracts and land

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