What Is The Import Relief?

In the United States and other countries, firms and workers who are injured by foreign competition attempt to get protection in the form of tariffs or quotas. Generally the U.S Department of Commerce and the U.S International Trade Commission analyze a petition for relief. Relief measures include the following actions:
The escape clause was popular in earlier periods. It allows temporary import relief when an industry has been injured by imports. Injury occurs when the output, employment, and profits in a domestic industry have fallen while imports have risen.

Antidumping tariffs are levied when foreign countries sell in the United States at prices below their average costs or at prices lower than those in the home market. When dumping is found, dumping duty is placed on the imported well.
Countervailing duties are imposed when foreigners subsidized exports to the United States. They became the most popular form of import relief and were pursued in hundreds of cases.    

Import relief may sound reasonable, but it actually runs completely counter to the economic theory of comparative advantage. I think this answer will satisfy your question.