In a technological sense, the world is flat so that "Free Trade Policy" is reasonable and applicable. However, as soon as it is realized that the world consists of institutionalized economies, we come to see "Free Trade Policy" is reasonable if trades occur among the economies which are the same or similarly institutionalized; whereas "Protective Trade Policy" is reasonable if trades occur between the economies which are heterogeneously institutionalized. As a Chinese scholar, beyond this tip I'd say no more!