Protectionism is a kind of economic interventionism which aims to protect the local industry from foreign competition. The most traditional forms of protectionist restrictions include tariffs and import quotas. Subsidies and restrictive government regulations may have equivalent effects, and thus can be considered as forms of protectionism.
Nowadays, mainstream economics consider that protectionism is most of the time inefficient and even impoverishes countries implementing it. There are particular situations in which a certain amount of protectionism might, in theory, be efficient. Yet, such situations are extremely rare because of the negative effects induced by trade retaliations of economic partners.
The different kinds of protectionism
It is the most common and classical form of protectionism. Tariffs are duties imposed on goods moved across a boundary. A tariff is said to be ad valorem when the duty is a percentage of the value of the good imported. On the contrary, a tariff is said to be specific when the duty is a specific amount of money whatever the price of the good concerned.