从历史上看 ,美国很早就有很强烈的经济保护主义倾向 ,即通过采用关税或配额的做法来限制外国货物的进口 ,以便保护本国工业。这项政策在美国早期的历史上便已出现 ,这可能是因为美国在地理上的孤立位置所致。由于新兴工业需要发展到一定的规模 ,才能获得规模经济的利益 ,如果 Historically, the United States has long tended to have a very strong tendency toward economic protectionism by restricting the import of foreign goods by adopting tariffs or quotas in order to protect their own industries. This policy has appeared in the early history of the United States, probably because of its geographically isolated position in the United States. As emerging industries need to develop to a certain size in order to gain economies of scale, if