As so often happens with tariffs, other countries retaliated. This tariff war restricted global trade, and was one reason for the extended severity of the Great Depression.
A second way of protecting trade is when the government subsidizes local industries with tax credits or even direct payments. This again lowers the price of locally produced goods and services. It works even better than tariffs because now the goods are cheaper even when shipped overseas.
This works well for the United States, but even better for countries that rely mainly on exports.