Introduction

As Southeast Asia moves into the twenty-first century, it has already been confronted with new security concerns such as the scourge of terrorism and the emergence of other sources of non-traditional security challenges that threaten the sovereignty and territorial integrity of regional states, as well as the cohesion of the region expressed through multilateral organizations such as the Association of Southeast Asian Nations (ASEAN) and the ASEAN Regional Forum. Michael Leifer was a student of regional institutions in Southeast Asia par excellence even before the formation of ASEAN. While Michael Leifer wrote extensively on archipelagic Southeast Asia, his point of entry into the region was Cambodia.