Modeled after the North Atlantic Treaty Organization it committed the nations to mutual cooperation and protection, as well as non-intervention in each other's affairs. Its goal was to contain the Soviet Union by having a line of strong states along it southwestern frontier.
The Middle East and South Asia became extremely volatile areas during the 1960s with the ongoing Arab-Israeli Conflict and the Indo-Pakistani Wars. The United States and CENTO were unwilling to get involved in either dispute. American support for Israel also damaged relations between the States and the Arab members. In 1965 and 1971 Pakistan tried unsuccessfully to get assistance in its wars with India through CENTO.
The pact also lead the United States to support corrupt and unpopular regimes in Iraq, Iran and Pakistan.
Most importantly the alliance did little to prevent the expansion of Soviet influence in the area. Other states in the Middle East felt excluded from CENTO and turned to the Soviets, including Egypt and Syria.
It lasted nominally until the Iranian revolution of 1979.