query: What's a tariff?
passage: Tariff
A tariff is a tax on imports or exports between sovereign states. It is a form of regulation of foreign trade. It is a policy that taxes foreign products to encourage or protect domestic industry. It helps limit trade deficits. The tariff is historically used to protect infant industries and to allow import substitution industrialization.
passage: Tariff
A crucial assumption in both the classical and neoclassical formulation of comparative advantage theory is that trade is balanced, which means that the value of imports is equal to the value of each country's exports. The volume of trade may change, but international trade will always be balanced at least after a certain adjustment period. The balance of trade is essential for theory because the resulting adjustment mechanism is responsible for transforming the comparative advantages of production costs into absolute price advantages. And this is necessary because it is the absolute price differences that determine the international flow of goods. Since consumers buy a good from the one who sells it cheapest, comparative advantages in terms of production costs must be transformed into absolute price advantages. In the case of floating exchange rates, it is the exchange rate adjustment mechanism that is responsible for this transformation of comparative advantages into absolute price advantages. In the case of fixed exchange rates, neoclassical theory suggests that trade is balanced by changes in wage rates.[54]