The catalyst for the Truman Doctrine had been Britain's February 1947 announcement that it could no longer afford to provide military or financial support to Greece and Turkey. This meant that these nations might fall to communism, and this was especially true for Greece, whose pro-Western government was fighting a communist guerrilla insurgency in the northern part of the country.
The eastern basin of the Mediterranean, including the Middle East, had historically been under British influence since the nineteenth century. The area was still important to Britain after World War II, but it took on great importance in light of the developing Cold War. Soviet presence in the region would jeopardize the ability of the Western powers to launch strategic air strikes on the Soviet Union from bases in the area. The defense of the region had been a British preserve and rested on British military bases, the largest of which was in Egypt. British power was declining, however, while at the same time Soviet activity in the region seemed on the increase.
The Soviet Union had demanded that the Turkish government change the rules governing ship movements through the Dardanelles and allow it to participate, along with other Black Sea nations, in the defense of the straits. The U.S. interpretation of the Soviets' demand was that they intended to secure hegemony over Turkey, build bases there, and then gain control over Greece. From there it could dominate much of the Middle East and the eastern Mediterranean. The demand in itself was of relatively minor importance because it was made in the form of a diplomatic note, not supported by any explicit or implicit military threats.
For planners in Washington, there seemed to be a power vacuum in the region, the result of Britain's declining strength. Britain was providing military aid to Turkey, but the U.S. Joint Chiefs of Staff (JCS) thought that because of its strategic importance and in order to increase its ability to meet Soviet aggression, the United States should increase its economic and military aid to Turkey. As long as the British furnished military assistance, however, the Truman administration would provide only economic aid.
American attitudes toward the situation in Turkey were linked to the situation in Greece. Like Turkey, Greece was considered a barrier between the Soviet Union and the Mediterranean. The struggle in Greece was not one inspired by the Soviet Union but rather resulted from conflict between rightists seeking to restore the monarchy who were also failing to tackle the grave economic situation and left-wing parties seeking to install a communist regime. Washington, however, chose to view the Greek Civil War through the lens of the Cold War. A loss in Greece to the communists would not only result in a victory for the Soviets but, it was argued, would also open the entire region to communist subversion. Thus, the Americans could not tolerate the establishment of a communist regime in Athens whether or not it was inspired by Moscow. Despite the shortcomings of the anticommunist Greek government, the Truman administration now moved to provide assistance to it. The decisive turning point came with London's announcement in February 1947 that Britain would be unable to continue its support to Greece and Turkey. It was obvious to U.S. State Department officials that the United States had to fill the breach. While preparing the draft legislation for the 1947 Greco-Turkish aid package, however, Undersecretary of State Dean Acheson found it difficult to justify the assistance request for Turkey, as it was not under a direct threat from either the Kremlin or an indigenous communist insurgency. Acheson also knew that Congress was in no mood to approve a large foreign aid request without proper justification, as it was engaged in efforts to curtail spending and pay down the national debt accrued during World War II. Also, Moscow was issuing conciliatory messages, further reducing the incentive in Congress to take strong measures against the Soviet Union.
Truman and his advisors, determined to provide military and economic assistance to both Greece and Turkey, had to find a way to sell this foreign aid package to Congress. Just prior to Truman's speech, Acheson described to the congressional leadership in stark terms the implications of Soviet domination over the eastern Mediterranean and the worldwide geopolitical consequences of such a scenario. In response, Republican Senator Arthur H. Vandenberg, a formerly steadfast isolationist, informed Truman that if he were to present his request to Congress in the manner that had been used by Acheson, he and the majority of Congress would support the aid deal. As a result, Truman's request for a $400 million aid package earmarked for Turkey and Greece was presented in the Cold War terms of a struggle "between alternate ways of life," marking the emergence of the Truman Doctrine, which came to represent a concerted long-term effort to resist communist aggression around the world. Vandenberg kept his promise. The Greco-Turkish aid package was speedily approved.
Lafeber, Walter. America, Russia and the Cold War, 1945–2002. Updated 9th ed. New York: McGraw-Hill, 2004.; Leffler, Melvyn P. A Preponderance of Power: National Security, the Truman Administration, and the Cold War. Stanford, CA: Stanford University Press, 1992.