http://www.truthout.org/yes-virginia-there-a-legitimate-case-against-free-trade58859Let's crack open that intimidating black box, shall we, and have a look at the machinery inside? Free trade has roughly ten very serious problems.
The first problem is the assumption that trade is sustainable. But a nation exporting non-renewable resources may discover that its best move (in the short run) is to export until it runs out. The flip side of this problem is overconsumption, in which a nation (like the present-day U.S., maybe?) borrows from abroad in order to finance a short-term binge of imports that lowers its long-term living standard due to the accumulation of foreign debt and the sale of assets to foreigners.
The second problem is that free trade increases inequality even if it makes the economy grow overall (which is itself questionable). Because free trade tends to raise returns to the abundant input to production (in America, capital) and lower returns to the scarce input (in America, labor), it tends to benefit capital at labor's expense. Economists call this the Stolper-Samuelson theorem.
The fourth problem is positive externalities, like the way some industries (mainly high technology) open up paths of growth for the entire economy. All industries are not alike, and the profits of an industry today do not necessarily predict the industry's long-term value for the economy. Free trade can allow these industries to be wiped out because it ignores this hidden value, harming the rest of the economy for decades to come.