Answer:
The Truman Doctrine was a foreign policy carried out during the Cold War. Its main purpose was to contain Soviet geopolitical expansion and it was further developed when the American Congress decided to support Greece and Turkey's armies since both nations were threatened by Communism.
The Declaration of Independence was the u.s. telling Great Britain that we wanted to be independent from them. The Constitution is the laws and principles of the Untied States. When something is questioned to be legal the constitution is consulted.
In the late 19th century, white settlers in the west clashed with Native American people over land and natural resources. When several tribes resisted settlement on reservations, the U.S. government fought for control in a series of conflicts called the “Indian Wars”
