— a phrase used by leaders and politicians in the 1840s to explain continental expansion by the United States — revitalized a sense of “mission” or national destiny for Americans
- The people of the United States felt it was their mission to extend the “boundaries of freedom” to others by imparting their idealism and belief in democratic institutions to those who were capable of self-government. It excluded those people who were perceived as being incapable of self-government, such as Native American people and those of non-European origin.
- The United States was experiencing a periodic high birth rate and increases in population due to immigration. And because agriculture provided the primary economic structure, large families to work the farms were considered an asset. The U.S. population grew from more than five millon in 1800 to more than 23 million by mid-century. Thus, there was a need to expand into new territories to accommodate this rapid growth. It’s estimated that nearly 4,000,000 Americans moved to western territories between 1820 and 1850.
- The United States suffered two economic depressions — one in 1818 and a second in 1839. These crises drove some people to seek their living in frontier areas.
- Frontier land was inexpensive or, in some cases, free.
- Expansion into frontier areas opened opportunities for new commerce and individual self-advancement.
- Land ownership was associated with wealth and tied to self-sufficiency, political power and independent “self-rule.”
- Maritime merchants saw an opportunity to expand and promote new commerce by building West Coast ports leading to increased trade with countries in the Pacific