Penelitian ini berusaha menjawab penyebab kegagalan aksi diplomasi koersi Republik Rakyat Tiongkok terhadap Korea Selatan pasca keputusan Korea Selatan untuk menggelar sistem pertahanan udara THAAD (Terminal High Altitude Area Defense) yang dianggap mengancam keamanan nasional Tiongkok. Pihak pemerintah Tiongkok menggelar aksi retaliasi berupa sanksi informal dalam bentuk boikot tidak langsung terhadap berbagai aspek ekonomi Korea Selatan seperti pariwisata, usaha perdagangan, produk produk dan budaya Korea Selatan / Hallyu. Diplomasi koersi yang Tiongkok lakukan menggunakan strategi Try and See dan Gradual Turning of the Screw pada awal 2016 hingga 2017 agar pemerintah Korea Selatan menarik kembali sistem pertahanan THAAD tersebut. Dengan menerapkan teori efektifitas diplomasi koersi serta metode kualitatif, penelitian ini menemukan jawaban bahwa tidak berhasilnya aksi diplomasi koersi yang dijalankan Tiongkok pada periode 2016-2017 diakibatkan dari tidak terpenuhinya variabel efektifitas diplomasi koersi yakni legitimasi tujuan dan permintaan, kredibilitas ancaman, reputasi aktor, asimetri motivasi, serta insentif yang ada.

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This study seeks analyze the causes of the failure of the People's Republic of China's coercive diplomacy against South Korea after South Korea's decision to deploy the THAAD (Terminal High Altitude Area Defense) air defense system which is considered a threat to China's national security. The Chinese government held a retaliation act in the form of informal sanctions of various aspects of the South Korean economy such as tourism, trade businesses, products and South Korean Hallyu culture. China's coercive diplomacy uses the Try and See and Gradual Turning of the Screw strategies in early 2016 to 2017 to get the South Korean government to withdraw the THAAD defense system. By using the theory of the coercive diplomacy effectiveness and qualitative methods, this study finds the answer that the failed coercive diplomacy attempt carried out by China in the 2016-2017 period resulted from the unfulfilled variables of the coercive diplomacy effectiveness, namely the legitimacy of goals and demands, credibility of threats, actor reputation, asymmetry of motivation, as well the incentives.