Tariff
In contrast, in economic theory tariffs are viewed as a primary element in international trade with the function of the tariff being to influence the flow of trade by lowering or raising the price of targeted goods to create what amounts to an artificial competitive advantage. When tariffs are viewed and used in this fashion, they are addressing the country's and the competitors' respective economic healths in terms of maximizing or minimizing revenue flow rather than in terms of the ability to generate and maintain a competitive advantage which is the source of the revenue. As a result, the impact of the tariffs on the economic health of the country are at best minimal but often are counter-productive.
History of taxation in the United States
While the government was originally funded via tariffs upon imported goods, tariffs now represent only a minor portion of federal revenues. Non-tax fees are generated to recompense agencies for services or to fill specific trust funds such as the fee placed upon airline tickets for airport expansion and air traffic control. Often the receipts intended to be placed in "trust" funds are used for other purposes, with the government posting an IOU ('I owe you') in the form of a federal bond or other accounting instrument, then spending the money on unrelated current expenditures.