The Truman Doctrine was a policy set forth by U.S. President Harry S Truman in a speech on March 12, 1947 stating that the U.S. would support Greece

History of Greece

The history of Greece encompasses the history of the territory of the modern state of Greece, as well as that of the Greek people and the areas they ruled historically. The scope of Greek habitation and rule has varied much through the ages, and, as a result, the history of Greece is similarly...

 and Turkey

History of Turkey

The history of the Turks begins with the migration of Oghuz Turks into Anatolia in the context of the larger Turkic expansion, forming the Seljuq Empire in the 11th century. After the Seljuq victory over forces of the Byzantine Empire in 1071 at the Battle of Manzikert, the process was accelerated...

 with economic and military aid to prevent their falling into the Soviet

Soviet Union

The Soviet Union , officially the Union of Soviet Socialist Republics , was a constitutionally socialist state that existed in Eurasia between 1922 and 1991....

 sphere

Eastern bloc

The term Eastern Bloc or Communist Bloc refers to the former communist states of Eastern and Central Europe, generally the Soviet Union and the countries of the Warsaw Pact...

. Historians often consider it as the start of the Cold War

Cold War

The Cold War was the continuing state from roughly 1946 to 1991 of political conflict, military tension, proxy wars, and economic competition between the Communist World—primarily the Soviet Union and its satellite states and allies—and the powers of the Western world, primarily the United States...

.

Truman stated the Doctrine would be "the policy of the United States to support free people who are resisting attempted subjugation by armed minorities or by outside pressures." Truman reasoned, because these "totalitarian regimes" coerced "free peoples," they represented a threat to international peace and the national security of the United States.