Barriers to international trade can take many forms, including:
However, most trade barriers all work on the same principle: the imposition of some sort of cost on trade that raises the price of the traded products. If two or more nations repeatedly use trade barriers against each other, then a trade war results.
Most economists agree that trade barriers are detrimental and decrease overall economic efficiency. Free trade involves the removals of all such barriers, except perhaps those considered necessary for health or national security.
See also
