Answer:
The number-one goal of the Truman Doctrine was to stop the spread of Communism in the world.
Step-by-step explanation:
President Harry S. Truman gave a historic speech at the American Congress on March 12, 1947, promising help to all countries that felt threatened by communist expansion. From then on there were two worlds: the "free world" and communism, or the First world and Second world. This speech is considered to be the beginning of the Cold War. Countries that previously fought against Nazi Germany as allies now faced each other.
A direct practical consequence was the financial assistance to Greece, where a left-wing coup was lurking, and Turkey, where the Soviet Union wanted to exert influence.
The Truman Doctrine led to the containment policy. Later in Asia this was further expanded through the Domino Theory.