Dulles became increasingly involved in politics at the onset of the Cold War. He represented the United States at the San Francisco organizational conference for the United Nations in 1945, and in many subsequent sessions of the United Nations General Assembly. He served as New York's junior senator from 1949 to 1950, replacing Senator Robert F. Wagner, who resigned due to ill health. Dulles then served as special representative of President Truman, with the rank of ambassador, negotiating the Japanese Peace Treaty of 1951 and the Australian, New Zealand, Philippine and Japanese Security Treaties of 1950-1951. During his negotiations, he observed the growing antagonism between the United States and Soviet Union which subsequently hardened his anti-Communist stance.
In 1953, President Dwight D. Eisenhower appointed Dulles Secretary of State. His tenure was marked by a close working relationship with the President, staunch anti-Communism, and a philosophy of "collective security" which led to numerous mutual defense treaties. Recognizing that NATO would only provide for the defense of Western Europe, Dulles initiated the Manila Conference in 1954 that resulted in the formation of the Southeast Asian Treaty Organization (SEATO), an agreement between eight nations for the defense of Southeast Asia, and was influential in establishing the 1955 Baghdad Pact for the defense of Turkey, Iraq, Iran, and Pakistan. He was also known for enunciating a policy of "massive retaliation," whereby any attack on U.S. interests anywhere in the world by the Soviet Union or China would be met with an attack on those countries, including the possible use of nuclear weapons.
Several notable international events marked Dulles's tenure. In 1955, in an effort to induce President Gamal Abdel Nasser of Egypt to support the West, Dulles offered to provide financing for the construction of the Aswan Dam on the Nile River to produce electrical power and for irrigation. However, Dulles withdrew the offer in July 1956 after receiving protests from United States cotton interests and Jewish-Americans, and after Nasser purchased weapons from Czechoslovakia, suggesting he was aligning with the Soviets. Nasser responded by nationalizing the British-owned Suez Canal. Without notifying the United States, Britain, France and Israel invaded Egypt in October 1956 but failed to capture the canal. Dulles condemned the action at the United Nations, and under economic pressure from the United States, the allies withdrew by early 1957.
Concurrent with the Suez crisis, an uprising in Hungary resulted in the establishment of a new government committed to withdrawing the country from the Warsaw Pact. The Soviets responded with military force, leading the Hungarians to appeal to the United Nations for aid, pleas that were ignored, allowing the Soviets to subsequently crush the revolt and maintain their grip on Eastern Europe.
In 1958, tensions between Communist China and Taiwan threatened to break out into war when Communist China renewed their shelling of the islands of Jinmen and Mazu and the United States avowed not to appease Mao Zedong. Dulles convinced Taiwan's Chiang Kai-shek to renounce the use of force against mainland China and to withdraw some troops from Jinmen and Mazu, and the Chinese ceased their shelling. Also in 1958, the Soviets threatened to sign a peace treaty with East Germany, terminating the joint occupation of Germany established after World War II, unless a satisfactory agreement was reached within six months. In what would be his last international trip as Secretary of State, Dulles traveled to Europe to reassure Chancellor Konrad Adenauer that the United States would maintain its commitment to West Germany. Eventually, the Soviets agreed to negotiate without a deadline.
Stricken with cancer, Dulles resigned as Secretary of State in April of 1959. He died on May 24, 1959 in Washington, D.C.
