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.
Non-tariff barriers to trade
One of the reasons why industrialized countries have moved from tariffs to NTBs is the fact that developed countries have sources of income other than tariffs. Historically, in the formation of nation-states, governments had to get funding. They received it through the introduction of tariffs. This explains the fact that most developing countries still rely on tariffs as a way to finance their spending. Developed countries can afford not to depend on tariffs, at the same time developing NTBs as a possible way of international trade regulation. The second reason for the transition to NTBs is that these tariffs can be used to support weak industries or compensation of industries, which have been affected negatively by the reduction of tariffs. The third reason for the popularity of NTBs is the ability of interest groups to influence the process in the absence of opportunities to obtain government support for the tariffs.