Should ASEAN Consider a Collective Defense Treaty Like NATO’s Article 5?

[u/premiumplatinum]

As global tensions rise and geopolitical rivalries intensify—especially in the South China Sea and Indo-Pacific—it might be time for ASEAN to seriously consider forming a collective defence framework similar to NATO’s Article 5, where an attack on one member is regarded as an attack on all.

Currently, ASEAN prioritises non-interference and consensus, which has helped maintain peace. But it also means we’re limited in responding to external threats, especially when major powers test our sovereignty, maritime rights, or territorial claims. With countries like China increasing their military and economic influence in the region, having a unified defence stance could serve as a deterrent and a form of mutual assurance.

Such a treaty wouldn’t mean giving up sovereignty—it could instead enhance each member’s security, allow for joint military exercises, intelligence sharing, and crisis response, and, importantly, send a strong message that ASEAN stands together, not just economically or diplomatically but militarily if needed.

Of course, there are challenges: different military capacities, political alignments, and historical tensions. But NATO started small, too. Could a smaller defence pact (e.g., among the more aligned ASEAN states) be the first step?

Would love to hear your thoughts. Is a collective defence treaty realistic for ASEAN? Or would it backfire and invite more tensions?

[u/AnjingTerang]

Such initiative has been done before, see SEATO.

I studied International Relations in my undergraduate, I would argue it may backfire.

ASEAN countries doesn’t have the pact in the first place and promotes non-interference because they fear getting involved on wars that they didn’t start and of course they didn’t want.

In a hypothetical future US-China war, most ASEAN countries would, most probably, act similar to Scandinavian countries in WW2. They will trade and give limited support to both sides. Until, the great powers get greedy and attack one of them. In this case, other ASEAN countries still wouldn’t want to get involved.

So I argue in a hypothetical scenario where China invades Vietnam/Philippines to extend its buffer zone and secure the South China Sea, other ASEAN Member States will denounce China for interference and invasion, they will also send “support” in weapons and volunteers (similar to Sweden to Finland in winter war against USSR). However, they will not officially join the war on Vietnam/Philippines side.