The Association of Southeast Asian Nations (ASEAN) has maintained an ambiguous position in security dynamics. While the organization upholds the principles of diplomacy, underpinned by non-interference and consensus, it also struggles to address security dilemmas and crises among its member states and toward sundry ongoing conflicts in the world. This chapter examines the historical foundations which have shaped ASEAN’s approach to security. Specifically, the objective of this chapter is twofold: first, to map ASEAN and its evolving attitudes toward conflicts and security, and second, to elaborate on the closely interlinked role and state of the military in relation to diplomacy and security concerns in Southeast Asia. The chapter uses the 2021 coup in Myanmar and the Russian invasion of Ukraine in 2022 as case studies to illustrate ASEAN’s security and diplomatic challenges. It argues that while ASEAN’s emphasis on dialogue has facilitated diplomatic engagements, it has failed to address security threats, maritime disputes, and democratic backsliding. Furthermore, the military often operates not only as defenders of sovereignty but even as prominent political entities affecting the functioning of the respective country and its political regime. Lacking any powers or enforcement mechanisms of its own, ASEAN remains constrained by its cooperative framework, limiting its ability to maneuver complex security landscapes.