Tariffs have historically played a key role in the trade policy of the United States. Economic historian Douglas Irwin classifies U.S. tariff history into three periods: a revenue period (ca. 1790–1860), a restriction period (1861–1933) and a reciprocity period (from 1934 onwards). In the first period, from 1790 to 1860, average tariffs increased from 20 percent to 60 percent before declining again to 20 percent. From 1861 to 1933, which Irwin characterizes as the "restriction period", the average tariffs rose to 50 percent and remained at that level for several decades. From 1934 onwards, in the "reciprocity period", the average tariff declined substantially until it leveled off at 5 percent. Especially after 1942, the U.S. began to promote worldwide free trade. After the 2016 presidential election which saw the election of Donald Trump who campaigned on a protectionist and economic nationalist political platform, the US increased trade protectionism.

According to Irwin, tariffs were intended to serve three primary purposes: "to raise revenue for the government, to restrict imports and protect domestic producers from foreign competition, and to reach reciprocity agreements that reduce trade barriers."

According to Irwin, a common myth about U.S. trade policy is that low tariffs harmed American manufacturers in the early 19th century and then that high tariffs made the United States into a great industrial power in the late 19th century. As its share of global manufacturing powered from 23% in 1870 to 36% in 1913, the admittedly high tariffs of the time came with a cost, estimated at around 0.5% of GDP in the mid-1870s. In some industries, they might have sped up development by a few years. However, U.S. economic growth during its protectionist era was driven more by its abundant resources and openness to people and ideas.

Tariff revenues

U.S. Historical Tariffs (Customs)and Tax Collections by the Federal GovernmentYearTariffIncomeBudget% TariffFederalReceiptsIncomeTaxPayroll TaxAverageTariff1792 $4.4 95.0% $4.6 $- $- 15.1%1795 $5.6 91.6% $6.1 $- $- 8.0%1800 $9.1 83.7% $10.8 $- $- 10.0%1805 $12.9 95.4% $13.6 $- $- 10.7%1810 $8.6 91.5% $9.4 $- $- 10.1%1815 $7.3 46.4% $15.7 $- $- 6.5%1820 $15.0 83.9% $17.9 $- $- 20.2%1825 $20.1 97.9% $20.5 $- $- 22.3%1830 $21.9 88.2% $24.8 $- $- 35.0%1835 $19.4 54.1% $35.8 $- $- 14.2%1840 $12.5 64.2% $19.5 $- $- 12.7%1845 $27.5 91.9% $30.0 $- $- 24.3%1850 $39.7 91.0% $43.6 $- $- 22.9%1855 $53.0 81.2% $65.4 $- $- 20.6%1860 $53.2 94.9% $56.1 $- $- 15.0%1863 $63.0 55.9% $112.7 $- $- 25.9%1864 $102.3 38.7% $264.6 $- $- 32.3%1865 $84.9 25.4% $333.7 $61.0 $- 35.6%1870 $194.5 47.3% $411.3 $37.8 $- 44.6%1875 $157.2 54.6% $288.0 $- $- 36.1%1880 $184.5 55.3% $333.5 $- $- 27.6%1885 $181.5 56.1% $323.7 $- $- 32.6%1890 $229.7 57.0% $403.1 $- $- 27.6%1900 $233.2 41.1% $567.2 $- $- 27.4%1910 $233.7 34.6% $675.2 $- $- 15.0%1913 $318.8 44.0% $724.1 $35.0 $- 17.6%1915 $209.8 30.1% $697.9 $47.0 $- 12.5%1916 $213.7 27.3% $782.5 $121.0 $- 8.9%1917 $225.9 20.1% $1,124.3 $373.0 $- 7.7%1918 $947.0 25.8% $3,664.6 $2,720.0 $- 31.2%1920 $886.0 13.2% $6,694.6 $4,032.0 $- 16.8%1925 $547.6 14.5% $3,780.1 $1,697.0 $- 13.0%1928 $566.0 14.0% $4,042.3 $2,088.0 $- 13.8%1930 $587.0 14.1% $4,177.9 $2,300.0 $- 19.2%1935 $318.8 8.4% $3,800.5 $1,100.0 $- 15.6%1940 $331.0 6.1% $5,387.1 $2,100.0 $800.0 12.6%1942 $369.0 2.9% $12,799.1 $7,900.0 $1,200.0 13.4%1944 $417.0 0.9% $44,148.9 $34,400.0 $1,900.0 10.6%1946 $424.0 0.9% $46,400.0 $28,000.0 $1,900.0 7.7%1948 $408.0 0.9% $47,300.0 $29,000.0 $2,500.0 5.5%1950 $407.0 0.9% $43,800.0 $26,200.0 $3,000.0 4.5%1951 $609.0 1.1% $56,700.0 $35,700.0 $4,100.0 5.5%1955 $585.0 0.8% $71,900.0 $46,400.0 $6,100.0 5.1%1960 $1,105.0 1.1% $99,800.0 $62,200.0 $12,200.0 7.3%1965 $1,442.0 1.2% $116,800.0 $74,300.0 $22,200.0 6.7%1970 $2,430.0 1.3% $192,800.0 $123,200.0 $44,400.0 6.0%1975 $3,676.0 1.3% $279,100.0 $163,000.0 $84,500.0 3.7%1980 $7,174.0 1.4% $517,100.0 $308,700.0 $157,800.0 2.9%1985 $12,079.0 1.6% $734,000.0 $395,900.0 $255,200.0 3.6%1990 $11,500.0 1.1% $1,032,000.0 $560,400.0 $380,000.0 2.8%1995 $19,301.0 1.4% $1,361,000.0 $747,200.0 $484,500.0 2.6%2000 $19,914.0 1.0% $2,025,200.0 $1,211,700.0 $652,900.0 1.6%2005 $23,379.0 1.1% $2,153,600.0 $1,205,500.0 $794,100.0 1.4%2010 $25,298.0 1.2% $2,162,700.0 $1,090,000.0 $864,800.0 1.3%--------------------------------------------------------------------------------------------Notes:All dollar amounts are in millions of U.S. dollars Income taxes include Individual and Corporate taxesFederal expenditures often exceed Revenue by temporary borrowings. Initially the U.S. Federal Government was financed mainly by customs(tariffs Average Tariff Rate % = Customs Revenue/ cost of Imports (goods).Other taxes collected are: Income Tax, Corporate Income Tax, Inheritance,Tariffs—often called Customs or duties on imports, etc. Income Taxes began in 1913 with the passage of 16th Amendment. Payroll taxes are Social Security and Medicare taxesPayroll Taxes began in 1940.Many Federal government Excise taxes are assigned to Trust Funds and are collected for and "dedicated" to a particular Trust. Sources: Historical Statistics of the United States (Colonial Times to 1957)Historical Statistics of the United States (Colonial Times to 1957); Value of Exports and Imports: 1790 to 1957, pp. 537–538; Value of Merchandise Imports and Duties: 1821 to 1957, p. 539; Indexes of Quantity and Unit Value of Exports and Imports: 1879 to 1957, pp. 540–541; Value of Merchandise Exports and Imports, by Groups of Customs Districts: 1860 to 1954, pp. 542–43; Value of Merchandise Exports and Imports, by Economic Classes: 1820 to 1957, pp. 544–545; Exports of Selected U. S. Merchandise: 1790 to 1957, pp. 546–547; Imports of Selected Products: 1790 to 1957, pp. 548–549; Value of General Imports, by Country of Origin: 1790 to 1957, pp. 552–553 Historical Statistics of the United States (Colonial Times to 1970)Historical Statistics of the United States (Colonial Times to 1970) {Part 2 Zip file: CT1970p2-12;} Series Y 343–51 (1940–1970) Customs, Tot. Receipts, Income taxes; Payroll taxes, Excise; Y342 339 (1940 1970) Receipts; Y-352 357 (1789–1939) Government Receipts: Total (1789–1970), Customs (1789–1970), Y 358 373 Excise tax (1863–1970) Income Tax (1916–1970); Series U 1–25 Balance of International Payments Imports (1790–1970) Accessed 5 Aug 2011 Bicentennial Edition Historical Statistics of the United States, Colonial Times to 1970Bicentennial Edition Historical Statistics of the United States, Colonial Times to 1970 Historical TablesWhitehouse Historical Tables 1940–2016; Table 1.1 Tot. Receipts (1901–2010); Table 2-1, 2–4 Excise Tax (1934–2010); Table 2-5 Customs (1940–2010) Accessed 5 Aug 2011 U.S. imports for consumption, duties collected, and ratio of duties to value, 1891–2016; U.S. imports for consumption under tariff preference programs, 1976–2016U.S. imports for consumption, duties collected, and ratio of duties to value, 1891–2016; U.S. imports for consumption under tariff preference programs, 1976–2016 U.S. Trade in Goods and Services-Balance of Payments (BOP) Basis, 1960–2010U.S. Trade in Goods and Services – Balance of Payments (BOP) Basis, 1960–2010 Accessed 5 Aug 2011

The evolution of U.S. tariff policy from 1790 to 2019 can be divided into three distinct periods, each characterized by a different primary objective: revenue generation (1790–1860), import restriction (1861–1933), and reciprocity through trade agreements (1934–present). During the revenue period, average tariffs increased from approximately 20% to 60%, before declining again to around 20% by 1860. In the subsequent restriction period, the average tariff on dutiable imports rose to roughly 50% and remained at that level for several decades. Beginning in 1934, the reciprocity period marked a sharp decline in tariff rates, which eventually stabilized at approximately 5%, a level that has persisted into the 21st century.

Many of the fluctuations in average tariffs over time were not the result of deliberate policy shifts, but rather due to changes in import prices interacting with “specific duties”—fixed dollar amounts per unit of quantity, rather than percentages of import value. For example, price increases during World War I and deflation during the Great Depression produced temporary spikes and dips in the average tariff level. A significant drop in tariffs following World War II was largely driven by inflation: roughly two-thirds of the decline between 1944 and 1950 resulted from rising prices, and one-third from tariff reductions negotiated at the first GATT conference in 1947.

Although the average tariff on dutiable imports has fluctuated considerably over time, the underlying tariff rates set by policymakers have been more stable than the raw data might suggest. These rates are typically structured to reflect the overarching goals of revenue generation, import restriction, or trade reciprocity.

Colonial Era and American Revolution Trade policy was a subject of controversy even prior to the independence of the United States. The thirteen North American colonies were subject to the restrictive framework of the Navigation Acts, which directed most colonial trade through Britain. Approximately three-quarters of colonial exports were enumerated goods that had to pass through a British port before being reexported elsewhere, a policy that reduced the prices received by American planters.

Scholars have long debated whether British mercantilist policies primarily benefited British shipping interests at the expense of the colonies, thereby contributing to the tensions leading to the American Revolution. In an early estimate, Harper (1939) calculated that these trade restrictions cost the colonies about 2.3% of their income in 1773. This estimate excludes potential benefits of imperial membership, such as reduced defense costs and lower shipping insurance rates due to Royal Navy protection. Nevertheless, British mercantilist restrictions are generally considered to have played a role in colonial demands for independence. It is estimated that about 90% of the economic burden imposed by the Navigation Acts fell on the southern colonies, particularly tobacco growers in Maryland and Virginia, potentially reducing regional income by up to 2.5% in 1770 and contributing to support for independence.

Available data from the era indicate that American foreign trade declined sharply during the Revolutionary War and remained subdued into the 1780s. Trade revived during the 1790s but remained volatile due to ongoing military conflicts in Europe.

Early National period, 1789–1828 The framers of the United States Constitution gave the federal government authority to tax, stating that Congress has the power to "lay and collect taxes, duties, imposts and excises, pay the debts and provide for the common defense and general welfare of the United States." and also "To regulate Commerce with foreign Nations, and among the several States, and with the Indian Tribes." Tariffs between states is prohibited by the U.S. Constitution, and all domestically made products can be imported or shipped to another state tax-free.

Responding to an urgent need for federal revenue and in light of concerns over the trade balance, the First United States Congress passed, and President George Washington signed, the Hamilton Tariff of 1789, which authorized the collection of duties on imported goods. Customs duties as set by tariff rates up to 1860 were usually about 80–95% of all federal revenue. Having just fought a war over taxation, among other things, the U.S. Congress wanted a reliable source of income that was relatively unobtrusive and easy to collect.Dewey, Financial History of the United States (5th ed. 1915) ch. 4–5