Even though the United States has many natural resources and the ways and means to use them in manufacturing, it cannot provide its people with all that they want or need. For this reason, the United States participates in international trade, which is the exchange of goods and services with other nations. Without international trade, goods would either cost more or not be available.

Throughout the world, there are substantial differences in the natural resources available. For example, Canada, with its huge forests, is a major producer of lumber and paper products; the Middle East has rich oil reserves; and the coastal regions of the world are leaders in the fishing industry.

Without international trade, each country would have to be totally self-sufficient. Each would have to make do only with what it could produce on its own. This would be the same as...