Answer:
Because they come directly from someone.
Explanation:
Other primary sources include photographs, diaries, documents, etc.
The civil war in Vietnam induced the united states to rethink Containment foreign policy strategy.
<h3>What is civil war in Vietnam?</h3>
The American Civil War existed as a civil war in the United States between the United States and the Confederacy. The central cause of the war was the level of slavery, especially the development of slavery in territories achieved as a result of the Louisiana Purchase and the Mexican–American War. The Vietnam War was represented as a civil war within South Vietnam, although it evolved into a proxy war between Cold War powers. As a consequence, the Vietnamese sorrowed the highest casualties in the conflict.
Containment existed as a foreign policy strategy observed by the United States during the Cold War. First laid out by George F. Kennan in 1947, the policy expressed that communism needed to be contained and isolated, or else it would extend to neighboring countries. The Truman Doctrine also understood as the policy of containment existed in President Harry Truman's foreign policy that the US would furnish political, military, and economic aid to democratic countries under the hazard of communist influences to control the expansion of communism.
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The threat was big to the Us
