FBI agents are not paid in hourly wages, they are paid through the federal government system GS ratings which provides agents an annual salary rating for years served.
The tariff of the United States, like all actual protective tariffs, is partly revenue and partly protective, its original purpose of yielding revenue having been subordinated to that of giving protection, until it may now be best described as a protective tariff yielding incidental revenue.
The purpose of a protective tariff is to protect domestic industry from foreign compitition. Say that it cost your country $10.00 to produce a widgit and your neighbour can produce and deliver one for $7.00. Odds are people are going to buy the imported one and your widgit industry will collapse and die.