This chapter analyzes Ukraine as the epicenter of renewed great-power rivalry, examining its dual role as both an object of competition and a subject with strategic agency. As an object, Ukraine’s fate is shaped by the competing instruments of external powers: Russia’s military aggression, energy coercion, and revanchist ideology are countered by the United States’ hard power patronage and the European Union’s normative and economic influence. As a subject, Ukraine has navigated this contest through evolving strategies, from post-Soviet hedging (1991–2004) and dual-tracking (2004–2013) to decisive shelter-seeking in Euro-Atlantic institutions since 2014. The chapter argues that Ukraine’s agency is bounded by significant constraints, including military attrition, internal elite fragmentation, and the institutional gatekeeping of NATO and the EU. The analysis also incorporates a post-sovereign lens, assessing how Russian-backed quasi-states in Crimea and Donbas magnify Ukraine’s vulnerabilities. The chapter concludes by projecting future scenarios for the conflict, contingent on the interplay between Western resolve and Russian resilience, and their implications for the European security order.