From irregular migration to illicit networks: operational emulation and cross-border crime in Sabah, Malaysia

The maritime tri-border region of the Sulu–Celebes Seas remains one of Southeast Asia’s most complex security zones where cross-border crime and violent extremism intersect. This study argues that the persistence of these threats arises not merely from porous borders or weak governance but from operational emulation, the strategic process through which criminal and extremist networks adapt by repurposing the infrastructures of irregular migration for survival and mobility. Drawing on a longitudinal case study, the paper demonstrates how illicit actors exploit socio-economic systems such as barter trade, smuggling, water villages and kinship networks, transforming them into operational architectures of transnational crime. Mechanisms of co-riding, camouflage, substitution, upgrading and insider intelligence enable these networks to embed within legitimate exchanges and evade enforcement. Rather than deterring illicit activity, measures such as pump-boat bans and intensified patrols often generate adaptive feedback loops, producing new routes, technologies and configurations. Conceptually, the paper contributes to border studies by reframing borderlands not as spaces of governance failure but as adaptive socio-economic ecologies, where livelihood systems and illicit networks co-evolve through iterative processes of adaptation. At the same time, operational emulation refines the crime-terrorism nexus by identifying concrete mechanisms through which cross-border illicit economies endure over time.