Final answer:
Members of a free trade agreement can set their own individual or collective tariff rates against non-member countries, often to protect domestic industries. Over time, there has been a strong global trend towards reducing trade barriers, partly through international agreements. The U.S. and other industrialized nations have significantly lowered their tariffs from the mid-20th century to the end of the century.
Step-by-step explanation:
In the case of a free trade agreement, the member countries generally agree to reduce or eliminate tariffs on mutual trade.
However, regarding tariff rates against the outside world, which are countries not part of the agreement, members may continue to enforce their own national laws or collective tariffs as they see fit, potentially to protect domestic industries or to negotiate better trade terms.
Over the past 60 years, there has been a trend towards lower trade barriers, with industrialized countries reducing their average tariff levels from 40% in 1946 to less than 5% after GATT negotiations by 1990.
The U.S. in particular has seen tariff rates decrease to less than 2% by the end of the 20th century. Additionally, international trade agreements like the WTO are seen as tools to help countries restrain domestic special interests that lobby for protectionism.