Tariff
A tariff is called an optimal tariff if it's set to maximize the welfare of the country imposing the tariff. It is a tariff derived by the intersection between the "trade indifference curve" of that country and the offer curve of another country. In this case, the welfare of the other country grows worse simultaneously, thus the policy is a kind of "beggar thy neighbor policy". If the offer curve of the other country is a line through the origin point, the original country is in the "condition of a small country", so any tariff worsens the welfare of the original country.
Tariff in United States history
Higher tariffs were adopted during and after the War of 1812, when nationalists such as Henry Clay and John C. Calhoun saw the need for more federal income and more industry. In wartime, they declared, having a home industry was a necessity to avoid shortages. Likewise owners of the small new factories that were springing up in the northeast to mass-produce boots, hats, nails and other common items wanted higher tariffs that would significantly protect them when the more efficient British producers returned after the war ended. A 10% discount on the customs tax was offered on items imported in American ships, so that the American merchant marine would be supported.