Then Adam Smith challenged this dominant thought in The Wealth of Nations, published in 1776.  Smith argued that if one nation is more efficient than another country in manufacturing a product, while the other nation is more efficient in manufacturing another product, then both nations could benefit from trade. This would allow each nation to specialize in the manufacture of the product, for which it had an absolute advantage, and thus increase total production over what it would be trade-free. This insight involved very different strategies from mercantilism. This is a reduction in government participation in the economy and a reduction in trade barriers. The comparative advantage theory starts from a world where trade between countries is balanced or, at the very least, where countries have a trade surplus or trade deficit, whether cyclical and temporary.  The easing of the assumption that “international trade between nations is balanced could lead a loss-making nation to import certain raw materials in which it would have a comparative advantage and which would in fact export with balanced trade,” says Dominic Salvatore. But he doesn`t see it as a major problem, “because most trade imbalances in relation to GNP are generally not very large.”  The benefits of unilateral removal of trade barriers are particularly evident in cases where the country does not produce the product; in these cases, removing barriers to trade broadens consumer choice. (However, as noted above, an exception appears in situations where removing a trade barrier for a raw material or component not produced by the land increases the effective protection rate of the finished product.) Trade agreements are useful because they allow countries to give Geza Feketukuty, the main US negotiator for the services of the Uruguay Round, a wonderful anecdote about the early efforts to start negotiations on trade in services: “The Swiss delegate … trade in services by pointing out how impossible it was for him to have his hair cut in another country by a hairdresser. The chairman of the committee.
. he replied that every woman in Germany had benefited enormously from French exports of hairdressing services, and she was convinced that the delegate`s wife would confirm that this was the case in Switzerland.  Yi notes that tariff reductions in these global supply chains have a greater impact than on traditional trade.