The ASEAN (Association of Southeast Asian Nations) has been around for about 50 years and members include but are not limited Thailand, Cambodia, Vietnam, Indonesia, Singapore, the Philippines. They originally formed to be stronger economically (such as removing tariffs) and to help resolve disputes between one another, in addition to curbing the Asian economic powerhouses’ economic strength: China and India.
I was copying the article from Japan Times but there was a disclaimer at the bottom saying that I cannot republish their article, so I will briefly summarize it.
After 13 years of not moving forward with ASEAN, the 10 member countries are now in agreement to work together. They signed it at Kuala Lumpur, Malaysia and the host of this summit, Malaysian Prime Minister Najib Razak, expressed this as a “landmark achievement.”
Since ASEAN is a group whose members are so diverse politically (communist, democratic, military dictatorship, authoritarian, monarchy, etc.), religiously (Buddhism, Islam*, Catholicism, etc.) and linguistically (various verbal and written languages), these variables will be challenging. These are just a few obstacles they will face before working working on the nitty gritty issues, such as the border dispute between Cambodia and Vietnam and curbing monopolies. Everyone has expressed that more work will be done.
*FYI: Indonesia is the country with the most Muslims, having about 25% of the world Muslim population.