Russia exploited China’s 19th-century weaknesses to seize territory through unequal treaties, later manipulating Chinese politics to delay unification. Stalin prioritized Soviet security by weakening China, undermining its post-WWII recovery by stripping Manchuria’s industry and blocking indemnities. After Stalin’s death, Mao recognized Soviet reluctance to support a strong China, fueling tensions that culminated in nuclear independence and border clashes. Deng Xiaoping’s reforms and U.S. alignment propelled China’s rise, contrasting with Soviet stagnation. Russia’s imperial pattern—dominating neighbors through institutional control—persists under Putin, though without ideological cohesion. Both nations now rely on nationalism amid eroding legitimacy, yet their strategic goals diverge: China focuses on Asia and Taiwan, Russia on Ukraine. Historical miscalculations, like those before the Russo-Japanese War, warn of self-inflicted crises. Ideological alignment failed to prevent the Sino-Soviet split, driven by structural rivalry and Stalin’s realpolitik. Today, Russia’s dependence on China risks reducing it to a satellite state, reversing historical power dynamics and highlighting the limits of zero-sum foreign policy in a cooperative global order.