Southeast Asia Collective Defense Treaty

The Southeast Asia Treaty Organization (SEATO) was a treaty organization formed on September 8 1954 by

• the United States,
• Great Britain,
• France,
• Australia,
• New Zealand,
• Pakistan,
• Thailand and
• the Philippines.

The organisation was headquartered in Bangkok. It was unable to intervene in the conflicts in Laos or Vietnam because such decisions required unanimity, which was never reached: France and the Philippines objected.

The SEATO was dissolved in 1977 and was replaced by ASEAN.