Abstract
This study investigates how the Collective Security Treaty Organization (CSTO) intervenes militarily in the affairs of member states. Through comparative case study and process-tracing methodology, cases of non-intervention including Kyrgyzstan, 2005, 2010, 2020; Armenia, 2021; Tajikistan-Kyrgyzstan, 2021–2; and Kursk, 2024 are compared to a single intervention that occurred in Kazakhstan, 2022. The analysis reveals that interventions are highly selective and not strictly driven by key provisions of the organisation's charter. The CSTO acts when domestic instability jeopardises a member regime’s survival, specifically when the state’s coercive apparatus loses reliability or control over its monopoly of violence. State breakdown within a CSTO member can create strategic risks for Moscow because the erosion of regime control over coercive institutions opens space for alternative political forces to seize power which may not be aligned with the regional hegemon’s interests. The anticipation of a non-aligned government emerging from state breakdown induces the CSTO to strategically interpret member state instability through the potentiality of domestic collapse and future strategic realignment. Hence, preventing the rise of hostile regimes is a core factor behind intervention.