Some employees in import industries where production is cut are likely to suffer periods of unemployment or have to take jobs that do not pay as well as their old ones. Owners in these same industries are likely to suffer declining profits. In economic terms, the losses borne by these groups are outweighed by the gains from trade, not only to consumers, but also to employees and owners in export industries, where trade causes production to expand. In principle, those who gain from trade could compensate those who lose from it. In practice, for political or other reasons, they typically do not.
Some people think it is much better for a country to export than import.
Suppose the United States and Thailand have the same amount of labor and other resources and that there is no trade, that is, each country has to be self-sufficient. Imagine that, using these resources, the US produces 400 thousand tons of apples and 300 thousand tons of rice from its resources, while Thailand produces 180 thousand tons of apples and 270 thousand tons of rice. They imply that the US has an absolute advantage in both commodities, but its comparative advantage is in apples because it is even more efficient at producing them than rice. Thailand has a comparative advantage in producing rice. The US produces more apples with trade than under self-sufficiency.