This thesis delves into the intricacies of understanding why Russia succeeded in annexing Crimea in 2014 while facing failure in its endeavours to capture Kyiv and other regions of Ukraine. Employing the lens of subversion theory, the study meticulously compares and contrasts the array of factors that influenced the outcomes of Russia's strategic manoeuvres in these distinct scenarios, scrutinizing them from a military standpoint. Through a comprehensive synthesis of diverse scholarly perspectives, the research endeavours to shed light on the pivotal role played by political manipulation, dissemination of disinformation, and backing of internal factions as critical determinants of subversion. The findings underscore the multifaceted nature of these subversive strategies and their profound implications for the unfolding events in Ukraine and the broader geopolitical landscape.