What Was the Southeast Asia Treaty Organization?

Instructor: Christina Boggs

Chrissy has taught secondary English and history and writes online curriculum. She has an M.S.Ed. in Social Studies Education.

After World War II, many countries were concerned about the spread of communism around the world. And so, in 1955, eight countries formed the Southeast Asia Treaty Organization, or SEATO. This lesson explains the origins and main purposes of SEATO.

After World War II

World War II officially came to an end in 1945 after roughly six years of conflict in Europe. While many countries breathed a sigh of relief that the war was over, others were gearing up for another conflict. After the war, there were two major world powers left standing: the United States and the Soviet Union. These two countries became locked in a global battle for ideological dominance, leading to the state of political tension known as the Cold War. The United States believed in spreading democracy, while the Soviet Union did its best to spread communism.

Within just a few short years after World War II, the U.S. fought to protect democracy in South Korea. Meanwhile, Communist China (backed secretly by the Soviet Union), fought for a communist North Korea. The Korean War marked the beginning of the long-standing U.S. policy of containment, which worked to make sure that the influence of communism did not spread to other parts of the world. Events in the post-war years ultimately lead to the formation of the Southeast Asia Treaty Organization (SEATO).

SEATO flag
SEATO flag

Forming SEATO

On Feb. 19, 1955, eight countries formed the Southeast Asia Treaty Organization. The group's mission was simple: Prevent communism from taking hold in Asia. Member countries included:

  • United States
  • United Kingdom
  • France
  • New Zealand
  • Australia
  • Pakistan
  • Thailand
  • Philippines

Oddly enough, only two of the eight member countries were actually located in Southeast Asia (Thailand and the Philippines)! So what reason did the other members have for joining? Australia and New Zealand are located in the Pacific not far from Southeast Asia, so proximity was a big factor. Pakistan was also located nearby (in South Asia), and it joined SEATO in hopes that it would receive assistance in its struggles with India (even though neither Pakistan nor India were under SEATO's jurisdiction).

The United Kingdom and France had close ties with Southeast Asia--both countries had colonies in the area before World War II. The United States' main purpose of joining SEATO was to curb communist influence, especially from China.

In addition to the members of SEATO, three countries were given observer status. Although they were not technically a part of SEATO, the following countries fell under the organization's protection:

  • Laos
  • Cambodia
  • Vietnam

Functions of SEATO

SEATO's main goal was to stop the spread of communism, and the organization did this in various ways. First, each country participated in yearly joint-military exercises, which involved different armed forces training together. Second, SEATO worked hard to build up the economies of countries in the region. The belief was that if people in Southeast Asia enjoyed a higher standard of living, then they would be less likely to succumb to communism. The organization was also responsible for hosting various regional events and promoting education initiatives.

SEATO conference in Manila, 1966
SEATO conference in Manila

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