Final answer:
Manifest Destiny caused westward migration and political support of territorial expansion in the United States.
Step-by-step explanation:
The concept of Manifest Destiny did indeed cause westward migration and political support of territorial expansion in the United States. Manifest Destiny was a belief held by many Americans in the 19th century that the United States was destined to expand across the North American continent from the Atlantic to the Pacific Ocean. This belief helped to justify and motivate westward migration, as well as political actions such as the annexation of Texas and the acquisition of territories from Mexico. It also influenced the cultural and religious justifications for American expansion and the treatment of Native Americans and other inhabitants of the territories.