Seeking to rally public support for the intervention, Eisenhower articulated the domino theory, which held that the fall of Vietnam could lead to the fall of other countries. As France refused to commit to granting independence to Vietnam, Congress refused to approve of an intervention in Vietnam, and the French were defeated at Dien Bien Phu. At the contemporaneous Geneva Conference, Dulles convinced Chinese and Soviet leaders to pressure Viet Minh leaders to accept the temporary partition of Vietnam; the country was divided into a Communist northern half (under the leadership of Ho Chi Minh) and a non-Communist southern half (under the leadership of Ngo Dinh Diem). Despite some doubts about the strength of Diem's government, the Eisenhower administration directed aid to South Vietnam in hopes of creating a bulwark against further Communist expansion. With Eisenhower's approval, Diem refused to hold elections to re-unify Vietnam; those elections had been scheduled for 1956 as part of the agreement at the Geneva Conference. Eisenhower's commitment in South Vietnam was part of a broader program to contain China and the Soviet Union in East Asia. In 1954, the United States and seven other countries created the Southeast Asia Treaty Organization (SEATO), a defensive alliance dedicated to preventing the spread of Communism in Southeast Asia. In 1954, China began shelling tiny islands off the coast of Mainland China which were controlled by the Republic of China (ROC). The shelling nearly escalated to nuclear war as Eisenhower considered using nuclear weapons to prevent the invasion of Taiwan, the main island controlled by the ROC. The crisis ended when China ended the shelling and both sides agreed to diplomatic talks; a second crisis in 1958 would end in a similar fashion. During the first crisis, the United States and the ROC signed the Sino-American Mutual Defense Treaty, which committed the United States to the defense of Taiwan. The CIA also supported dissidents in the 1959 Tibetan uprising, but China crushed the uprising. The Middle East became increasingly important to U.S. foreign policy during the 1950s. After the 1953 Iranian coup, the U.S. supplanted Britain as the most influential ally of Iran. Eisenhower encouraged the creation of the Baghdad Pact, a military alliance consisting of Turkey, Iran, Iraq, and Pakistan. As it did in several other regions, the Eisenhower administration sought to establish stable, friendly, anti-Communist regimes in the Arab World. The U.S. attempted to mediate the Israeli–Palestinian conflict, but Israel's unwillingness to give up its gains from the 1948 Arab–Israeli War and Arab hostility towards Israel prevented any agreement.