This study of the successes and failures of US economic interventions shows that aid can be successful when it is provided in significant amounts, supports equitable asset distribution (e.g. land reform) and is accompanied by access to US markets for sale of the less developed country's products. Economic aid to Korea and Taiwan, established before the development of Cold War anticommunist policies, helped these countries achieve economic development. On the other hand, post-Cold War aid to various countries in Southeast Asia and Central America supported reactionary, ineffective and unpopular governments, and produced institutional changes whose purpose was political (anticommunist) rather than economic. With the waning of the Cold War, US aid and trade policies in Costa Rica in the 1980s again met with success because the relevant governments' social democratic politics produced similar institutional foundations as were present in the Taiwan and Korean cases.