The Tariff Act of 1789, was the first major Act passed in the United States under its present Constitution of 1789 and had two purposes as stated in Section I of the Act which reads as follows;
Whereas it is necessary for that support of government, for the discharge of the debts of the United States, and the encouragement and protection of manufactures, that duties be laid on goods, wares and merchandise[1]
Tariffs were used back in the day because the federal government had to raise funds to pay for services.
Tariffs in today’s world are used to punish or get even with a country.
The concept of “Fair Trade” obviously escapes you.