Non-tariff is an obstacle to free trade other than a tariff
Tariffs are a tax imposed on imported goods
Protectionism is measures taken by a country to restrict international trade
Quotas are an agreement by a country to limit its exports to another country to a given quantity
Protectionism motivations are:
Response to import dumping
Response to chronic trade gap/deficits
Employment protection
Protect infant sectors
Protect key strategic industries
Raise extra revenues for government
Response to recession/stagnation in domestic demand
Import dumping refers to when firms sell products abroad at below costs, an example would be China's steel industry dumping products in the European Union
Trade creation occurs when a customs union results in high-cost domestic production being replaced by imports from a more efficient source within the customs union
Trade diversion occurs when a customs union results in trade switching from a low-cost supplier outside the customs union to a less efficient source within the customs union