Penelitian ini bertujuan untuk menjelaskan mengapa kerja sama keamanan berhasil dilakukan dan berjalan efektif, meskipun terdapat sensitivitas antarnegara. Hal ini terjadi dalam kesepakatan kerja sama keamanan maritim di Laut Sulu pada tahun 2016, yaitu Trilateral Cooperative Arrangement (TCA), yang berhasil mereduksi ancaman keamanan di Laut Sulu di tengah isu sengketa wilayah Sabah antara Malaysia dan Filipina. Klaim atas wilayah Sabah yang dilontarkan oleh Presiden Rodrigo Duterte pada tahun 2016 menimbulkan sensitivitas dalam hubungan antara Malaysia dan Filipina. Namun, pada saat yang sama, ancaman di Laut Sulu akibat kejahatan transnasional semakin meningkat. Dengan menggunakan teori kerja sama dalam sistem anarki, penelitian ini berargumen bahwa kerja sama antara Filipina dan Malaysia terwujud karena adanya tiga faktor. Ketiga faktor tersebut adalah adanya kepentingan bersama Malaysia dan Filipina terhadap Laut Sulu, proyeksi kekhawatiran atas ancaman di masa depan, dan jumlah aktor serta pemilihan mitra kerja sama yang sesuai. Melalui pendekatan kualitatif dan metode causal-process tracing, ditemukan bahwa ketiga faktor ini mendorong Malaysia dan Filipina untuk memprioritaskan kerja sama dalam mengatasi ancaman keamanan di Laut Sulu serta mengesampingkan sensitivitas akibat sengketa wilayah Sabah.

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This research aims to explain why security cooperation can be successfully carried out and effectively run despite the sensitivities between the cooperating countries. This can be observed in the Trilateral Cooperative Arrangement (TCA) in the Sulu Sea in 2016, which effectively reduced security threats in the Sulu Sea despite the Sabah territorial dispute between Malaysia and the Philippines. In 2016, President Rodrigo Duterte's claim to the Sabah region reignited tension between Malaysia and the Philippines. But at the same time, the threat in the Sulu Sea from transnational crime was increasing. By applying the theory of cooperation under anarchy, this research demonstrates that cooperation between Malaysia and the Philippines is feasible due to three key factors: both Malaysia and the Philippines have a mutuality of interest in the Sulu Sea, they are concerned about future security threats, and numbers of actors involved and partner selection. Through a qualitative approach and causal-process tracing method, this research found that these three factors led Malaysia and the Philippines to prioritize addressing security threats in the Sulu Sea, considering it a paramount concern. As a result, the two countries prioritize forging a cooperative agreement over the issue of the Sabah dispute.