The Era of Good Feelings was a period of dramatic growth and intense nationalism. The spirit of nationalism was apparent in Supreme Court decisions that established the supremacy of the federal government and expanded the powers of Congress. American interest and power in foreign policy was especially apparent in the Monroe Doctrine. Industrial development enhanced national self-sufficiency and united the nation with improved roads, canals, and river transportation.
Forces for division were also at work. The financial Panic of 1819 led to the emergence of new political parties. The Missouri Crisis contributed to a growing sectional split between North and South.