Following the annexation of Crimea by Russia, it was predicted by numerous academics, policymakers, and media sources that Moscow would use its military in a similar manner in the rest of Ukraine. However, contrary to these predictions, Moscow used various hybrid tools and tactics, such as targeted media operations, material support for ethnic-based movements, as well as covert security operations. Such tools and tactics have become a defining feature of gray zone conflicts, which dominate the mode of contemporary interaction between geopolitical adversaries. The question this research addresses is why does Russia use various intensities of coercive tools and tactics across its near abroad? This thesis builds a theoretical model of foreign policy decision-making through the synthesis of system-level incentive and domestic-level opportunity causal variables. A structured-focused comparison through discourse and content analysis is used to assess the validity of the causal mechanisms in the Incentive-Opportunity Intervention (IOI) Model. This study focuses on the cases of Russia's decisions to use various gray zone tools and tactics in 1) Abkhazia, 2) Crimea, 3) Odessa, 4) Kharkiv, and 5) the Donbas region. The testing of the hypotheses is conducted through two process-tracing tests: 1) the 'hoop test' and 2) the 'smoking gun test.' For each hypothesis, there is a sequence of necessary observations to support causal inference. The observations in each case are identified through the gathering of empirical evidence in three stages. This study finds that the variation in Russia's application of gray zone tools and tactics is a function of 1) different system-level role decline risks relative to power across its 'near abroad' as well as 2) varying costs associated with support for non-state actors in different ethnic-based movement types. In terms of implications for conflict management, this study challenges the conventional approach of addressing geopolitical threats with military means. Rather, security threats in gray zone conflicts may be addressed effectively through 'civilian' means. To this end, a key focus of bilateral and multilateral conflict management efforts in gray zone conflict should be domestic-level institutional structures in states which become the battlegrounds of great power politics.