The Truman Doctrine was the political statement; the North Atlantic Treaty of April 4, 1949 was its legal and military translation. The doctrine of March 1947 had committed the United States to support free peoples resisting communist pressure; NATO’s Article 5 committed the United States and eleven European partners to treat an armed attack on any one of them as an attack on all. The crises that fell between them — the communist coup in Czechoslovakia in February 1948 and the Berlin Blockade beginning in June 1948 — convinced the Truman administration and a Senate majority that a treaty commitment was needed.
From the Doctrine to a Treaty
The Truman Doctrine of March 1947 had been deliberately vague on military matters. It promised aid to Greece and Turkey and a general commitment to support countries resisting communist pressure, but it created no institutional mechanism and contained no pledge of automatic military response. Within a year, the administration concluded that the doctrine was not enough.
Two events forced the change. The first was the communist coup in Czechoslovakia, February 25, 1948, in which the Czechoslovak foreign minister Jan Masaryk died — by suicide or murder; the evidence remains unclear — and a fully Soviet-aligned government took power. The coup removed the last functioning democracy in Eastern Europe and demonstrated the limits of economic aid without a security guarantee. The second was the Soviet blockade of West Berlin, beginning June 24, 1948, in which the USSR cut off land and rail access to the Western sectors of the city. The eleven-month crisis ended with the successful Berlin Airlift, but it had shown that Western Europe could not defend itself against Soviet conventional superiority without American ground and air power.
The Vandenberg Resolution
The constitutional obstacle to a peacetime military alliance was significant. The Senate had resisted the League of Nations in 1919–1920 and the heavier lifting that any Atlantic alliance implied. The breakthrough came in the form of the Vandenberg Resolution, adopted by the Senate on June 11, 1948, by a vote of 64–4. The resolution, named for Senator Arthur Vandenberg of Michigan, declared that the United States could, “by constitutional process,” join “regional and collective self-defense arrangements.” It cleared the diplomatic ground for the treaty negotiations that followed.
The North Atlantic Treaty was signed in Washington on April 4, 1949, by twelve countries: the United States, Canada, the United Kingdom, France, Italy, Belgium, the Netherlands, Luxembourg, Norway, Denmark, Iceland, and Portugal. Greece and Turkey joined in 1952, the Federal Republic of Germany in 1955.
Article 5
The treaty’s core was Article 5, by which the parties agreed that “an armed attack against one or more of them in Europe or North America shall be considered an attack against them all.” Each signatory pledged to take “such action as it deems necessary, including the use of armed force,” to restore and maintain security. The United States deliberately did not specify what actions would follow an attack; the Constitution, not the treaty, would determine the domestic form of the American response. The Senate gave its advice and consent on July 21, 1949, by a vote of 83–13.
NATO was the institutional expression of what the Truman Doctrine had declared as a principle. The doctrine articulated the political will; the treaty made the will a binding legal obligation, and created a permanent command structure in Europe (initially SHAPE, the Supreme Headquarters Allied Powers Europe, established in 1951) to back it up. The connection between the two is most clearly visible in the people who built them: George C. Marshall, the architect of both the doctrine and the treaty; Dean Acheson, the undersecretary who drafted the speech and pushed the treaty; and George Kennan, the strategic mind that informed both. For the strategic framework, see the Truman Doctrine and containment.