The Indian Removal Act opened land that Indigenous peoples had previously called home to White settlement and the expansion of slavery, further codifying injustices at the federal level that had long been underway.

In 1823, U.S. President James Monroe declared the United States the protector of the Western Hemisphere, prohibiting European powers from establishing new colonies in the Americas. Concurrently, Monroe pledged that the U.S. would not meddle in the internal affairs, conflicts, or existing colonial endeavors of European nations.

The Constitution established innovative governmental doctrines and practices, including checks and balances, the separation of powers among branches, and the definition of these powers. Furthermore, the amendment process allows the Constitution to be a dynamic document, amendable with sufficient public support and state ratification.

Great Depression is increased

acceptance of the government's role in creating social welfare programs and a recognition of the need for government intervention during economic downturns

An important event that occurred in 1803, the Louisiana Purchase, gave the United States enormous new territory after it paid $15 million to France for 828,000 square miles. This calculated action caused the country to double in size, spurred westward migration, and had long-lasting effects on the country's evolution, including discussions about federal power and slavery.