http://www.newyorker.com/talk/financial/2008/05/26/080526ta_talk_surowiecki
"But it’s safe to say that the main burden of trade-related job losses and wage declines has fallen on middle- and lower-income Americans. So standing up to China seems like a logical way to help ordinary Americans do better. But there’s a problem with this approach: the very people who suffer most from free trade are often, paradoxically, among its biggest beneficiaries.
The reason for this is simple: free trade with poorer countries has a huge positive impact on the buying power of middle- and lower-income consumers—a much bigger impact than it does on the buying power of wealthier consumers. The less you make, the bigger the percentage of your spending that goes to manufactured goods—clothes, shoes, and the like—whose prices are often directly affected by free trade. The wealthier you are, the more you tend to spend on services—education, leisure, and so on—that are less subject to competition from abroad."