1967 Six Day War:
On the morning of June 5, 1967, Israel launched a preemptive strike against Egyptian forces in response to Egypt's closing of the Straits of Tiran. By June 11, the conflict had come to include Jordan and Syria. As a result of this conflict, Israel gained control over the Sinai peninsula, the Golan Heights, the West Bank, the Gaza Strip and East Jerusalem. Israeli claims on these territories, and the question of the Palestinians stranded there, posed a long term challenge to Middle East diplomacy.
Since the Arab-Israeli War of 1948, the Israelis had clashed intermittently with Palestinian Arabs and Arab forces from the neighboring states. By the mid-1960s, these incidents intensified causing increased diplomatic tensions in the Middle East. On April 7, 1967 a skirmish on land turned into a major air battle during which Israel shot down six Syrian MiG aircraft over Mount Hermon on the Golan Heights. This led President Gamal Abdel Nasser of Egypt immediately offered to assist Syria in the event of a future Israeli attack.
On May 13, Nasser received a secret message from the Soviet Union, which supplied both Egypt and Syria with weapons, informing him that Israel had massed troops on the Syrian border. Nasser took immediate steps to uphold his pledge to Syria. On May 14, he mobilized his army, and, three days later, he asked United Nations Secretary General U Thant to remove the United Nations Emergency Forces that had been stationed on the Sinai Peninsula since the end of the Suez Canal Crisis of 1956. The Secretary General agreed to a full withdrawal. Nasser then closed the Straits of Tiran on May 21 to all shipping both to and from Israel.
U.S. President Lyndon B. Johnson condemned the Egyptian blockade of the Straits of Tiran and tried to discourage a war while still supporting Israel. Although Arab nations believed that Johnson would support an Israeli military action, the United States did not want to be drawn into another armed conflict as it was already committed to fighting the Vietnam War. In a public address on May 23, President Johnson denied Egypt's right to interfere with the shipping rights of any nation in the Gulf of Aqaba and committed the United States to supporting the rights of all the nations in the region. He warned that the United States would oppose aggression by any state in the area but encouraged diplomatic negotiations.
By the end of May, despite diplomatic efforts, tensions continued to rise. The withdrawal of the United Nations forces from the Sinai, the redeployment of Egyptian troops to the Sinai, the massing of hostile forces on the Israeli border, and the signing of a Mutual Defense Pact between Egypt and Jordan on May 30, weakened U.S. efforts to dissuade Israel from taking military action. The war began on June 5, 1967, when Israeli airplanes attacked the Egyptian air force and destroyed many airfields. Between June 5 and June 11, Israeli Defense Forces led onslaughts against Egyptian forces in Sinai and Gaza, and against the Jordanian military in East Jerusalem and the West Bank. The conflict ended with significant battles against Syrian forces on the Golan Heights between June 9 and 10. By June 11, Israel controlled territory previously held by the Arabs in the Sinai, the Golan Heights, the West Bank, the Gaza Strip and East Jerusalem.
The United States and the Soviet Union did not intervene in this conflict and pledged that they would make every effort to end the fighting. Soviet and U.S. officials cooperated in the United Nations Security Council to broker cease-fire agreements.
Following the war, the issue of the return of Israel-occupied territories received most attention. U.S. President Johnson spoke out against any permanent change in the legal and political status of the Israeli-occupied territories and emphasized that Arab land should be returned only as part of an overall peace settlement that recognized Israel's right to exist. The principle of land for peace was embodied in United Nations Security Council Resolution 242 adopted in November 1967. Resolution 242 called for the Israeli withdrawal from the territories it had occupied following the 1967 war in exchange for peace with its neighbors. The land for peace formula served as the basis for future Middle East negotiations.