Throughout history, many great nations have amassed an immense empire through
expansionism, which is a nation's practice or policy of territorial or economic expansion.
The United States expansionism was present since it became an independent nation itself.
Manifest Destiny, which is the doctrine that the United States had the right and duty to
expand throughout the North American continent played a major role in expansionism of the
mid 1800ís. Evidence such as the Louisiana Purchase, the acquisition of California, and
the Oregon Territory shows expansion of the United States from the Atlantic Ocean to the
Pacific. Although expansionism in the late 1800ís and the early 1900ís was a departure
from past expansionism, it also was a continuation in some aspects.
At the turn of the century, Americans looked past the contiguous United States to overseas
empires. This expansionism movement was much the same to the expansionism movement of the
early 1800ís in which Americans pushed from the Appalachians to the Pacific. In both
instances, United States citizens moved into the new territories, joining the natives.
Americans brought with them diseases that plagued the natives, and often killed large