This article traces the institutional history of the United States Congress from its colonial and revolutionary antecedents through the present day. For constitutional and structural background, see the main topic page. For legal interpretation, see United States Congress - Legal Consensus.
Representative assemblies appeared in the American colonies as early as 1619, when the Virginia House of Burgesses convened at Jamestown. By the mid-18th century, each of the thirteen colonies maintained a legislative body that handled local taxation, appropriations, and governance. These assemblies developed traditions of deliberation, representation by district, and assertion of legislative prerogative against royal governors that would directly inform the design of the national legislature.
The First Continental Congress convened in Philadelphia in September 1774, bringing together delegates from twelve colonies to coordinate a response to the Coercive Acts. It was not a legislature in the full sense but an ad hoc deliberative body. The Second Continental Congress, which first met in May 1775, assumed broader governing functions as hostilities with Britain escalated. It issued the Declaration of Independence in July 1776, managed the Continental Army, conducted diplomacy, and functioned as the de facto national government throughout the Revolutionary War.
The Articles of Confederation, ratified in 1781, established the Congress of the Confederation as a unicameral body in which each state held one vote regardless of population. It lacked the power to tax directly, regulate commerce, or compel state compliance with its resolutions. Experience under the Articles shaped the Constitutional Convention's deliberations on legislative structure.
The Constitutional Convention met in Philadelphia from May to September 1787. Delegates disagreed sharply over legislative representation. The Virginia Plan proposed a bicameral legislature with representation proportional to population in both chambers. The New Jersey Plan called for equal representation per state in a unicameral body. The Connecticut Compromise - also called the Great Compromise - resolved the dispute by creating a bicameral Congress: a House of Representatives apportioned by population and a Senate with two seats per state regardless of population.
The Constitution was signed on 17 September 1787 and ratified by the requisite nine states by June 1788. The First Congress convened on 4 March 1789 in New York City. It established the executive departments, passed the Judiciary Act of 1789 organizing the federal courts, and drafted the twelve amendments sent to the states for ratification - ten of which were ratified as the Bill of Rights in 1791.
The early Congresses operated in a context of intense disagreement over the scope of federal legislative authority. Secretary of the Treasury Alexander Hamilton's financial program - including assumption of state debts, a national bank, and an excise tax - generated the first major constitutional disputes over implied congressional powers. Opposition coalesced around James Madison and Thomas Jefferson, eventually forming the Democratic-Republican Party in opposition to Hamilton's Federalists.
The Alien and Sedition Acts of 1798, passed by a Federalist Congress, criminalized criticism of the federal government and tightened naturalization requirements. The Virginia and Kentucky Resolutions, drafted by Madison and Jefferson respectively, asserted that states could judge the constitutionality of federal legislation - a position that prefigured later nullification arguments.
Congress moved from Philadelphia to the newly constructed Capitol in Washington, D.C., in 1800. The building was burned by British forces during the War of 1812 and subsequently rebuilt.
The Missouri Compromise of 1820 admitted Missouri as a slave state and Maine as a free state, and prohibited slavery in the Louisiana Territory north of latitude 36°30'. It represented the first major congressional attempt to manage the sectional conflict over slavery's expansion.
The antebellum period was defined in Congress by escalating conflict between slaveholding and non-slaveholding states. The Nullification Crisis of 1832-1833 arose when South Carolina declared the federal tariffs of 1828 and 1832 null and void within its borders. Congress passed the Force Bill authorizing the president to use military force to collect tariffs; a compromise tariff defused the immediate crisis.
The Compromise of 1850, engineered largely by Senator Henry Clay and shepherded through Congress by Senator Stephen Douglas, admitted California as a free state, organized the Utah and New Mexico territories without restriction on slavery, abolished the slave trade in the District of Columbia, and enacted a strengthened Fugitive Slave Act. The Kansas-Nebraska Act of 1854, sponsored by Douglas, repealed the Missouri Compromise line and established popular sovereignty as the mechanism for determining slavery's status in new territories. It produced the “Bleeding Kansas” conflict and accelerated the collapse of the Whig Party and the formation of the Republican Party.
The Compromise of 1850's Fugitive Slave Act and its congressional enforcement were among the most contested legislative actions of the period, generating significant resistance in Northern states. The caning of Senator Charles Sumner of Massachusetts on the Senate floor in May 1856 by Representative Preston Brooks of South Carolina became a widely reported symbol of sectional hostility.
When Southern states began seceding following the election of Abraham Lincoln in November 1860, their congressional delegations withdrew. The remaining Congress enacted sweeping legislation including the Homestead Act (1862), the Morrill Land-Grant Act (1862), the Pacific Railroad Acts (1862, 1864), and the National Banking Act (1863) - legislation that had been blocked for years by Southern opposition.
The Thirteenth Amendment, abolishing slavery, passed Congress in January 1865 and was ratified in December of that year. The Fourteenth Amendment (1868) established birthright citizenship and equal protection of the laws. The Fifteenth Amendment (1870) prohibited denial of voting rights on the basis of race.
Reconstruction-era Congresses passed the Civil Rights Act of 1866, the Reconstruction Acts of 1867 dividing the former Confederate states into military districts, and the Enforcement Acts of 1870-1871 targeting Ku Klux Klan violence. Congress impeached President Andrew Johnson in 1868 over his violation of the Tenure of Office Act; he was acquitted by one vote in the Senate.
The Compromise of 1877, resolving the disputed presidential election of 1876, resulted in the withdrawal of federal troops from the South and the effective end of Reconstruction.
The late 19th century saw Congress dominated by Republican majorities for most of the period, with significant power concentrated in party leadership and congressional committees. The Senate in particular was criticized as responsive to corporate and railroad interests; senators were elected by state legislatures rather than directly by voters until ratification of the Seventeenth Amendment in 1913.
Major legislation of the period included the Interstate Commerce Act (1887), establishing federal regulation of railroads; the Sherman Antitrust Act (1890); the Chinese Exclusion Act (1882); and the Dawes Act (1887), which restructured Native American land tenure.
Speaker of the House Thomas Brackett Reed imposed new procedural rules in 1890 - over intense minority objection - that prevented filibuster-like obstruction in the House by refusing to permit members to avoid being counted as present. Speaker Joseph Cannon's autocratic control of the House led to a bipartisan revolt in 1910 that stripped the speakership of its power to appoint committee members and chair the Rules Committee.
The Sixteenth Amendment (1913) authorized a federal income tax. The Federal Reserve Act (1913) established the central banking system. The Clayton Antitrust Act (1914) strengthened antitrust law. Congress declared war on Germany in April 1917.
Republican Congresses of the 1920s enacted high protective tariffs, restricted immigration through the Emergency Quota Act (1921) and the Immigration Act of 1924, and generally reduced federal economic intervention. The Senate rejected membership in the League of Nations in 1919-1920, a significant exercise of its treaty ratification role.
The onset of the Great Depression in 1929 and the election of Franklin Roosevelt in 1932 brought Democratic supermajorities to Congress. The 73rd Congress (1933-1935) passed the legislation of the First New Deal in rapid succession, including the Banking Act, the Agricultural Adjustment Act, the National Industrial Recovery Act, and the creation of the Civilian Conservation Corps and the Tennessee Valley Authority.
The Senate Munitions Investigating Committee, chaired by Gerald Nye of North Dakota, held hearings from 1934 to 1936 on the role of arms manufacturers and bankers in drawing the United States into World War I. The Neutrality Acts of 1935-1937 were passed in the same period.
Congress declared war on Japan on 8 December 1941, the day after the attack on Pearl Harbor, and on Germany and Italy on 11 December. It appropriated the funds for wartime mobilization and passed the Lend-Lease Act (1941) prior to American entry into the war.
The Legislative Reorganization Act of 1946 reduced the number of congressional committees, increased staff resources, and required lobbyists to register.
The postwar period saw significant legislative output: the Taft-Hartley Act (1947) restricting labor union activities; the National Security Act (1947) reorganizing the defense establishment; the Marshall Plan appropriations (1948); and the creation of NATO (ratified 1949). The Senate's Army-McCarthy hearings in 1954 were nationally televised and contributed to the censure of Senator Joseph McCarthy.
The Civil Rights Act of 1964 and the Voting Rights Act of 1965 were landmark statutes passed after protracted congressional debate. The Civil Rights Act overcame a 57-day Senate filibuster - the longest in Senate history to that point - with the support of a bipartisan cloture vote. The Immigration and Nationality Act of 1965 abolished the national-origins quota system established in 1924.
The War Powers Resolution of 1973, passed over President Nixon's veto, required the president to notify Congress within 48 hours of committing armed forces to hostilities and limited unauthorized engagements to 60 days. The Budget and Impoundment Control Act of 1974 established the Congressional Budget Office and the current congressional budget process.
The House Judiciary Committee voted to recommend articles of impeachment against President Nixon in July 1974; Nixon resigned before a full House vote. President Clinton was impeached by the House in December 1998 on charges of perjury and obstruction of justice and acquitted by the Senate in February 1999.
Republicans gained control of the House in 1994 for the first time since 1954, under the leadership of Speaker Newt Gingrich and around the “Contract with America” platform. The shift ended a 40-year period of Democratic House dominance and marked a significant change in congressional procedure and partisan dynamics.
The Authorization for Use of Military Force, passed on 18 September 2001 following the September 11 attacks, authorized the president to use force against those responsible for the attacks and became the legal basis for subsequent military operations in Afghanistan and elsewhere. The USA PATRIOT Act, passed in October 2001, expanded surveillance authorities.
The Affordable Care Act (2010) was passed without Republican votes through the reconciliation procedure. The Dodd-Frank Wall Street Reform and Consumer Protection Act (2010) overhauled financial regulation following the 2007-2008 financial crisis.
President Donald Trump was impeached twice by the House - in December 2019 on charges of abuse of power and obstruction of Congress, and in January 2021 on a charge of incitement of insurrection following the 6 January 2021 Capitol breach. He was acquitted by the Senate on both occasions.
The use of the filibuster, once relatively rare, became routine in the Senate in the early 21st century, effectively requiring a 60-vote supermajority for most legislation. Both parties invoked the “nuclear option” to eliminate the filibuster for executive and judicial nominations - Democrats in 2013 for most nominations, Republicans in 2017 for Supreme Court nominations.