Tariffs cause deadweight loss because they move the price of an imported product closer to the equilibrium without trade, thus reducing the gains from trade.

Deadweight Loss

A loss of economic efficiency that can occur when the equilibrium for a good or a service is not achieved, leading to a decrease in total surplus.

Tariffs

Taxes imposed by a government on imported goods. They are used to restrict imports by increasing the price of goods and services purchased from abroad, making them less attractive to consumers.

Equilibrium

A condition where the amount of goods supplied in the market matches the demand, leading to steady prices and quantities.