Let me explain the theory behind the answer by using an example of a medical doctor and her typist. Assume that a doctor in Korea makes 100,000 won an hour. The doctor needs a typist to take care of her patient records and invoices. So she, the doctor, hires a typist. The doctor pays her typist 5,000 won per hour. Now we make an interesting assumption that the doctor can type faster than her typist. In other words, the doctor can take care of patients better than her typist and the doctor can also type better than her typist. Should the doctor hire the typist? Now the answer seems much easier and is obviously yes. What happened?
It all depends on the opportunity cost of the doctor and her typist. The opportunity cost of taking care of typing duties for the doctor is 95,000 won. In other words, the doctor may save 5,000 won by doing the typing duties for her self, but will be losing 100,000 won that she could earn if she takes care of her patients rather than typing during the same hour. The opportunity cost of taking care of typing for the typist is 5,000 won at the most. In other words, it is more expensive for the doctor to take care of typing than it is for her typist to do the typing work. In this case, the typist who can carry out the typing duties cheaper should specialize in typing, while the doctor should specialize in taking care of patients even if the doctor is a better typist.
http://www.truthabouttrade.org/article.asp?id=4274
Note: http://www.truthabouttr...

Free trade simply beggars the "rich" partner's workforce by providing cheap goods and labour that can be sold in the "rich" country for a bit cheaper than can be produced in the "rich" country. This eliminates employment and income in the "rich" country as we have seen with dramatic effect here in Canada.
Should the "poor" country get uppity and actually start demanding a living wage, the trade deals just move to the next disadvantaged country, abandoning the uppity country and causing even more economic hardship.
Free trade (as it is practiced) is no kind of blessing for any country, it is a curse. It is a windfall cash cow for a few, very rich, corporations and persons.
At the end of the article the author writes:
"Before I conclude, let me revisit the theory of comparative advantages, which suggests that free trade will benefit all trading countries. What the theory tells us is true over a long period of time and policy makers of all nations continue to try to reduce tariffs to promote free trade among all nations. In the short run, however, there are conflicting interests and problems. For instance, we do not know whether the theory will help developing countries that are not capable of producing quality products that can compete in the global market place. We also do not know exactly why the volume of intra-industry trade, such as Japan and the U.S. exporting automobiles to each other, increases so rapidly among nations when the theory of comparative advantages suggests a complete specialization."
So:
- the theory suggests wonderful things for the long term
- in practice the short term produces conflicting intersts and problems
- in practice, short term empirical data shows a marked divergence from expectations.
In other sciences, you'd go back to the drawing board.
Imagine! All things should fall up. If they fell up, simulations indicate the potenital energy of all things would increase indefinitely and life would be grand. We should get governments worldwide to agree that things should fall up. Short term empiracle evidence shows various problems amongst fall-up governments so far unexplained by the model. In many cases, in the short term, things dropped appear to fall down instead, acutally losing potential energy. In the long term, though, remember that things falling up will benefit everyone, so governments should stay the course.
Ah, economics. The only "science" that tells the world what it "should" do.