Protectionism is the economic policy of promoting favoured domestic industry through the use of high tariffs or other regulations to discourage imports. A tariff is a tax placed upon imports (and/or export goods), sometimes called customs duty. A revenue tariff is set with the intent of raising money for the government. A protective tariff, usually applied to import goods, is intended to artificially inflate prices if imports and "protect" domestic industries from foreign competition. This latter is the method applied by the US, which is mentioned in the article.

Fig.1

As illustrated in Fig.1, the domestic price before trade is Po with quantity produced at Qdo. After trade, which leads to a shifting out of the supply curve, the price falls to the world...