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
Once industrialization and mass production started, the demand for higher and higher tariffs came from manufacturers and factory workers. They believed that their businesses should be protected from the lower wages and more efficient factories of Britain and the rest of Europe. Nearly every northern Congressman was eager to logroll a higher tariff rate for his local industry. Senator Daniel Webster, formerly a spokesperson for Boston's merchants who imported goods (and wanted low tariffs), switched dramatically to represent the manufacturing interests in the Tariff of 1824. Rates were especially high for bolts of cloth and for bar iron, of which Britain was a low-cost producer. The culmination came in the Tariff of 1828, ridiculed by free traders as the "Tariff of Abominations", with import custom duties averaging over 25 percent. Intense political opposition to higher tariffs came from Southern Democrats and plantation owners in South Carolina who had little manufacturing industry and imported some products with high tariffs. They would have to pay more for imports. They claimed their economic interest was being unfairly injured. They attempted to "nullify" the federal tariff and spoke of secession from the Union (see the Nullification Crisis). President Andrew Jackson let it be known he would use the U.S. Army to enforce the law, and no state supported the South Carolina call for nullification. A compromise ended the crisis included a lowering of the average tariff rate over ten years to a rate of 15% to 20%.