Final answer:
The Truman Doctrine pledged American support to freedom fighters opposing communism, marked by President Truman's 1947 address to Congress. It led to U.S. intervention in Greece and Turkey with significant financial aid and established a policy of containment to limit the spread of Communism during the Cold War.
Step-by-step explanation:
The Truman Doctrine pledged American support to freedom fighters opposing communism. On March 12, 1947, President Harry S. Truman articulated this principle in an address to Congress, requesting aid for Greece and Turkey. The doctrine was a clear signal that the United States would oppose totalitarian regimes and provide assistance to nations threatened by communist expansion.
Following Truman's announcement, the United States intervened to prevent the spread of Communism, as seen with the allocation of $400 million in aid to Greece and Turkey. This intervention helped Greece defeat communist rebels and supported Turkey in maintaining control of crucial areas such as the Dardanelles. Through this policy, the United States demonstrated its commitment to the policy of containment, with an overarching goal of limiting communism to the countries where it had already taken root.
Throughout the Cold War, similar sentiments were echoed in later policies such as the Reagan Doctrine, which suggested that the U.S. must back the armed forces of any regime fighting against Communist forces, emphasizing a continued American willingness to support anti-Communist movements worldwide.