Oh really?
Country A has no tariffs on the goods it imports.
They are trading with country B.
To protect it’s own domestic orange growing industry they pass a 50% tariff on the Oranges they import from A.
Fair trade has just ended because there is no longer free trade.
A then reciprocates with a 50% tariff on all goods imported from B and says it will remain in place until B drops the tariff on oranges.
B drops the tariff, we now have a level playing field and A drops it’s tariffs as well.
We now have fair and free trade between A and B.