A lingering puzzle in the studies of post-World War II American foreign policy is why US Cold War policy in industrialized democracies diverged from its approach in less-developed countries; why America, in containing subversive forces, emphasized industrial expansion in Western Europe, but "policing operations" in the Third World. This question carries weight in that a probe for its answer could not only illuminate the nature of Cold War conflict but also explain America's still uneasy relations with some less-developed countries. Building on world system theory but expanding it further, I argue that politico-economic attributes of the region, toward which US policy is directed, account for the disparate outcomes. As the hegemonic power, the United States after World War II bore the brunt of tearing down obstacles that hampered the expansion of the market economy and its "political underpinning," liberal democracy. An array of challenges to this task was not uniform, however, because distinctive political development ensued in different parts of the capitalist system. High-profit business undertakings afforded the core a viable capital-labor alliance in the mid-20^th century. Politics overall stable here, the United States encountered little systemic threat and dispensed with heavy-handed interventionism. In postwar Germany, the United States groomed the ally as the engine of European recovery by facilitating reindustrialization. Presence of capital-intensive industries bequeathed West Germany flexible labor-management relations, and the reign of liberal democracy obviated the need of hegemonic intervention. Low value-added economic activities in the periphery, in the meantime, rendered interclass compromise not feasible. Utilizing manual labor extensively, factory owners and landlords here were ill disposed towards economic concessions and working-class empowerment. Impoverished, disenfranchised workers/peasants frequently threatened the survival of free market, and this triggered America's armed intervention. Post-colonial Korea inherited the agitated masses, who suffered through the feudalistic land tenure system and the police state under the Japanese rule. Upon liberation, awakened workers/peasants formed grassroots organizations and called for thorough political, economic reform. Because these revolutionaries could not be co-opted, the United States neutralized them with force and aligned the emerging South Korean republic with the anti-Communist bloc.