Key Concept 5.1

The United States became more connected with the world as it pursued an expansionist foreign policy in the Western Hemisphere and emerged as the destination for many migrants from other countries.

I. Enthusiasm for U.S. territorial expansion, fueled by economic and national security interests and supported by claims of U.S. racial and cultural superiority, resulted in war, the opening of new markets, acquisition of new territory, and increased ideological conflicts.

• The idea of Manifest Destiny, which asserted U.S. power in the Western Hemisphere and supported U.S. expansion westward, was built on a belief in white racial superiority and a sense of American cultural superiority, and helped to shape the era's political debates.
• The acquisition of new territory in the West and the U.S. victory in the Mexican-American War were accompanied by a heated controversy over allowing or forbidding slavery in newly acquired territories.
• The desire for access to western resources led to the environmental transformation of the region, new economic activities, and increased settlement in areas forcibly taken from American Indians.
• U.S. interest in expanding trade led to economic, diplomatic, and cultural initiatives westward to Asia.
  • clipper ships, Commodore Matthew Perry's expedition to Japan, missionaries

II. Westward expansion, migration to and within the United States, and the end of slavery reshaped North American boundaries and caused conflict over American cultural identities, citizenship, and the question of extending and protecting rights for various groups of U.S. inhabitants.

• Substantial numbers of new international migrants - who often lived in ethnic communities and retained their religion, language, and customs - entered the country prior to the Civil War, giving rise to a major, often violent nativist movement that was strongly anti-Catholic and aimed at limiting immigrants' cultural influence and political and economic power.
  • parochial schools, Know-Nothings
• Asian, African American, and white peoples sought new economic opportunities or religious refuge in the West, efforts that were boosted during and after the Civil War with the passage of new legislation promoting national economic development.
  • Mormons, the gold rush, the Homestead Act
• As the territorial boundaries of the United States expanded and the migrant population increased, U.S. government interaction and conflict with Hispanics and American Indians increased, altering these groups' cultures and ways of life and raising questions about their status and legal rights.
  • Mariano Vallejo, Sand Creek Massacre, Little Big Horn