2) Reduce Reliance and Mistrust of Foreign Powers. There were several reasons. The most important reason was that with the withdrawal of colonial powers, there would have been a power vacuum which would have attracted outsiders to step in for political gain within Southeast Asia as the colonial masters had discouraged any form of intra-regional contact.
The idea of neighbours working together in a joint effort was thus to be encouraged. Secondly, organisations such as the Southeast Asia Treaty Organisation (SEATO) co-operation among disparied members located in distant lands can be ineffective.Southeast Asian countries therefore had to strive to build co-operation among those who lived close to one another and shared common interests. Thirdly, the need to join forces became imperative for the Southeast Asian countries in order to be heard and to be effective. The motivation for ASEAN to band together was thus to strengthen and protect themselves against Big Powers rivalry.
Also, due to the Vietnam War whereby North and South Vietnam were split, the USA and USSR each took one side to support.This caused fear in the newly-independent countries as they did not want foreign superpowers interfering in their matters like they did in Vietnam. Another example that supported the formation of ASEAN was Indonesia’s president, Sukarno, who proposed the formation of a regional group to advocate for neutrality in the USA and USSR rivalry and band together to stand up against the foreign powers.
Finally, it is common knowledge that cooperation and ultimately integration served the interests of all – something that individual efforts can never achieve.