現代全球化對比較優勢理論的挑戰
現在的全球化不同於早先的全球化。我們知道，經濟全球化的理論基礎之一是比較優勢理論。比較優勢理論是兩百年前由英國經濟學家李嘉圖提出的。按照比較優勢理論，如果每個國家都集中生產並出口自己具有比較優勢的產品，進口其具有比較劣勢的產品，那麼到頭來，交易雙方都可以增進自己的利益。然而，李嘉圖的比較優勢理論是建立在一系列理論前提之上的，其中很重要的一條是，生產要素在一國之內可以自由流動，在兩國間則不能流動。在李嘉圖的時代，國與國的自由貿易只限於產品。在當時，資本和私人企業是不會移動的，是留在本國的。今天的經濟全球化，卻是在產品自由流動之外，還加上了資本和私人企業的自由流動。人員的流動也增加了，不過人員的流動總有各種障礙，因而總是緩慢的、有限的；而資本的流動則易如反掌，十分快捷。既然比較優勢理論賴以成立的理論前提發生了重大改變，因此，原先從比較優勢理論推出的結論也就不一定還成立了。
不錯，中美之間的經濟交往與貿易給兩國的經濟都帶來了可觀的收益，但是在一國之內，不同群體的收益情況卻可以很不相同。在美國，跨國資本是最大的受益者，而失去工作的勞工則是相對的乃至絕對的受害者；在中國，最大受益者是政府。另外，兩國的受益情況也不等同，總的來說，中國受益要比美國大。
The current globalization is different from the earlier form of globalization. As we know, one of the theoretical foundations of economic globalization is the theory of comparative advantage. The theory of comparative advantage was proposed by the British economist David Ricardo two hundred years ago. According to this theory, if each country specializes in producing and exporting goods in which it has a comparative advantage while importing goods in which it has a comparative disadvantage, both trading parties will ultimately benefit. However, Ricardo's theory of comparative advantage is based on a series of theoretical assumptions, one of the most important being that factors of production can move freely within a country but cannot move between countries. In Ricardo's time, free trade between nations was limited to products. At that time, capital and private enterprises did not move across borders; they remained within their home countries.
Today's economic globalization, however, goes beyond the free movement of products to include the free movement of capital and private enterprises. Although labor mobility has also increased, it still faces various obstacles and is therefore slow and limited, whereas capital flows with ease and at a rapid pace. Since the fundamental assumptions supporting the theory of comparative advantage have undergone significant changes, the conclusions originally derived from this theory may no longer hold.
Indeed, economic interactions and trade between China and the United States have brought considerable benefits to both economies. However, within each country, different groups experience different outcomes. In the United States, multinational capital is the biggest beneficiary, while workers who have lost their jobs are relative or even absolute losers. In China, the biggest beneficiary is the government. Additionally, the overall benefits are not equal between the two countries; generally speaking, China has gained more than the United States.