Structure and powers of Congress. (2003). In D. R. Tarr, & A. O'Connor (Eds.), Congress A to Z. Washington: CQ Press. Retrieved August 19, 2005, from CQ Electronic Library, CQ Encyclopedia of American Government

Structure and Powers of Congress

Under the Constitution, Congress is charged with carrying out the legislative functions of government. The framers of the Constitution wanted the lawmaking role to be in the hands of a representative body. They considered Congress, the collective name for the Senate and House of Representatives, to be the “first branch” of the U.S. government, the primary maker of national policy. The powers, structure, and procedures of the national legislature are outlined in considerable detail in the Constitution, unlike those of the presidency and the judiciary, the other independent branches in the American system of separation of powers.

Checks and Balances

Each branch is structured so that it may restrain the others' excesses, resulting in a form of institutionalized “checks and balances.” Within Congress itself the legislative power is checked in many ways. To a degree the House and Senate are competitors, even when both are controlled by the same party. And that rivalry can be seen no matter which party is in control. Each chamber seeks to protect its own powers and prerogatives. The Constitution helps to create the competition—that is, the checks—by giving some powers to the Senate alone and others to the House. Powers reserved to the Senate include approval of treaties, confirmation of presidential nominations, and the power to try impeachments. Granted to the House alone is the authority to originate impeachments and all revenue-raising bills.

Although competition and conflict are built into the system, cooperation between House and Senate is essential because legislation must be passed in identical form by both chambers before it can be sent to the president for approval or veto. A form of checks and balances between branches comes into play once Congress has finished acting on a bill. The president may veto any bill that Congress sends him, forcing legislators to consider the chief executive's opinions and priorities. Congress, however, may override the president's action by a two-thirds vote of both chambers. The actions of both the legislative and executive branches are at least implicitly checked by the review functions of the national judiciary.

Another form of checks and balances derives from the system of federalism, the countervailing forces of the state and federal governments. Federalism is a factor to be reckoned with in the legislative process. Because members of Congress are elected either from a state or from a congressional district within a state, local and regional interests strongly influence how the laws are drafted. This often creates tensions between the House and Senate and between Congress and the executive branch.

Members in modern Congresses are seldom dependent on their national party apparatus for their election. Senators or representatives who are popular back home usually cannot be forced to heed the wishes of the president or their party's congressional leaders. This independence is a result of many modern developments, including television, direct mail, and campaign-financing trends. It is a significant change from historical patterns, under which political parties and major party leaders were able to control the political conduct and votes of members.

Congress's Many Roles

Congress by design is untidy, unwieldy, and unrestrained. But an independent, decentralized, and deliberative legislature is exactly what the framers of Article I of the Constitution had in mind.

Members' constituents are not united on most issues most of the time, and a halting, indecisive Congress usually mirrors the public at large. The framers of the Constitution did not look upon efficiency as the primary goal in lawmaking. Sensitive to what they viewed as the denial of basic human rights under British rule, and to other failings of eighteenth-century governments, they were mainly concerned with ensuring individual rights and liberties. Within the federal government they feared the potential excesses or domination of one branch over the others, and in Congress they feared the domination of a majority over the minority.

The Constitution, then, provides the framework of a complicated system of government. Some of the complexities become quickly apparent when tracing the steps involved in the legislative process. Legislation must follow an intricate course before it can become law. Each step presents potential barriers to passage and gives legislators opportunities to kill or modify bills or provisions they oppose.

Many experts on Congress have observed that the legislative process resembles an obstacle course that favors the opponents of legislation over the proponents. There are many points at which bills can be stymied or delayed and relatively few effective tools for speeding passage through Congress, particularly when members differ strongly over issues. Although opponents have the upper hand in most situations, members also are under pressure to get legislation enacted, especially programs in the domestic field that can benefit their districts, states, or regions—a public works project, for example, or a navy ship-building contract. Therefore, bargaining, compromise, and logrolling are necessary to offset the institutional bias against speedy enactment of bills.

President as Legislative Leader

The modern president plays the principal role in setting the legislative agenda. Congress expects the White House to submit proposals for new laws dealing with the whole spectrum of foreign and domestic policy. When existing programs come up for renewal, Congress generally waits for the executive branch to present its recommendations before setting the legislative wheels in motion. Although the Constitution implies that the president should play the leading role, this was not the general practice during the nineteenth century.

A nineteenth-century scene in the Old Senate Chamber. (Source: Library of Congress.)

The president uses a variety of vehicles and forums to present his program to Congress and the nation. Best known is the annual State of the Union address, which is a constitutional requirement. Article II, Section 3 of the Constitution directs the president periodically to “give to the Congress Information of the State of the Union, and recommend to their Consideration such Measures as he shall judge necessary and expedient.”

Equally important is the president's annual budget message, with its accompanying documents. The budget message contains many of the president's legislative goals for the coming year, as well as requests for money to run the federal government. The agenda also is shaped by periodic messages and statements proposing new measures or changes in pending bills. Even presidential veto messages may contain recommendations for future legislation.


The legislative branch is bicameral, meaning that it consists of two houses, or chambers. Representatives are elected for two-year terms; senators, for six-year terms. Before adoption of the Seventeenth Amendment to the Constitution in 1913, senators were elected by their state legislatures.

Senators represent entire states, while House members represent population-based districts within the states. States that have very small populations relative to the others qualify for only one representative in the House. For these, the entire state is the congressional district and is referred to as an at-large district. In the 108th Congress (2003–2005), there were seven at-large districts: Alaska, Delaware, Montana, North Dakota, South Dakota, Vermont, and Wyoming. Congress has passed a law prohibiting House members from being elected at large in states that have more than one representative.

Traditionally House members were considered to represent the people more closely than senators because of their short terms and small constituencies. Although facing reelection every two years does tend to force representatives to view their roles somewhat differently than senators do, this distinction is fast disappearing. The major factors are the pervasive influence of television—including gavel-to-gavel coverage of both Senate and House floor debates—and other media coverage, and the ease with which members can return to their states and districts. These factors make senators and representatives equally accessible to the public and aware of the views of the citizens they represent. Earlier, senators were drawn closer to their constituents when they became subject to direct election.

The complexities of the legislative process require Congress to operate through elaborate rules as well as informal practices that have been refined, modified, and changed over the years. Except where the Constitution delineates the powers and parliamentary procedures, each chamber has developed its own set of rules from the body of traditions and precedents that developed during more than 200 years of legislating. Size alone accounts for many of the differences in the organization of the two bodies and in the rules and customs each has adopted. The House requires a more formal structure and detailed rules; the smaller Senate legislates in an informal setting and may not follow its formal rules if it prefers not to.


The Constitution sets only three qualifications for membership in Congress. They are:

  • Age: A House member must be at least twenty-five years old; a senator, at least thirty.

  • U.S. citizenship: A House member must have been a citizen for at least seven years; a senator, for at least nine.

  • Residency: A senator or representative must be a resident of the state from which he or she is elected.

Since adoption of the Twentieth Amendment in 1933, members' terms have begun on January 3 of the year following their election. That amendment also made January 3 the beginning of each new two-year term of Congress, and January 20 the date that newly elected presidents take office. The original constitutional language regulating when sessions of Congress began, and the precedents Congress followed in its first 140 years, proved inefficient for timely lawmaking and unrepresentative of the most recent general-election results. Elections are held on the first Tuesday following the first Monday in November in even-numbered years.


The Senate, as mandated by the Constitution, consists of two senators from each state. Senators' terms are staggered. Only thirty-three or thirty-four Senate seats—one-third of the membership—are at stake in each biennial general election. For this reason the Senate considers itself a continuing body, and its rules continue in effect from one Congress to the next. The House adopts its rules at the beginning of each Congress.

The size of the House is determined by Congress itself, within certain constitutional prescriptions. Throughout the nineteenth century the membership of the House was increased to reflect the growth of the nation's population and the addition of new states to the Union. In 1910 the size of the House was set at 435 members, where it has remained ever since, except for a brief period (1959–1963) after Alaska and Hawaii were admitted to statehood, when it was increased to 437.

The size of each state's House delegation is determined by the results of the census, which is conducted every ten years. The Constitution specifies that House seats must be reapportioned among the states after every census to reflect population growth and shifts in population from one state to another since the last census. (No reapportionment took place after the 1920 census because Congress could not agree on any plan to reapportion House seats.)

Ever since the House decided to keep its membership at 435, reapportionment has resulted in some states gaining seats at the expense of others. After the reapportionment following the 2000 census, House districts averaged about 645,000 constituents. (See Reapportionment and Redistricting.) In addition to its 435 voting members, the House has five delegates. They represent the District of Columbia, Puerto Rico, the Virgin Islands, Guam, and American Samoa.

Powers of Congress

The many explicit powers of Congress enumerated in the Constitution reflect in part the framers' experience with the woefully weak Congress under the Articles of Confederation, the nation's original plan of government. Under the Articles, Congress was practically powerless to protect the national interest. It could not limit encroachment on the federal government's authority by the thirteen independent states. The Constitution's detailed, precise enumeration of many of Congress's powers, principally in Article I, Section 8, reflects the fears and distrust between the various states and blocs of states at the time the document was drafted. Although these powers are extensive, most of them are shared with the other two branches, particularly the executive. Thus the Constitution established a system not of separate powers but of separate institutions sharing powers and functions.

The Tenth Amendment specifies that powers not expressly delegated to Congress or the other branches, and not prohibited by the Constitution, are reserved to the states or to the people.

Domestic Powers

Foremost among Congress's powers is the right “to lay and collect taxes, duties, imposts and excises, to pay the debts [and]… to borrow money on the credit of the United States.” Article I, Section 9 stipulates that no federal funds can be spent except “in consequence of appropriations made by law.” Three key powers are involved here: taxing, borrowing, and spending. They are known collectively as the power of the purse.

Most of the time members spend on legislative work is occupied with measures that either directly or indirectly involve these three powers. Although certain limitations are placed on how Congress can legislate under these powers, raising and spending money, or committing the federal government to spend money in the future, lie at the heart of congressional decision-making.

Congress also is charged with providing for the “general welfare.” These two words have provided the underpinning for the whole list of public assistance programs enacted by the modern Congress that are taken for granted today: Social Security, agricultural subsidies, workers' unemployment and disability insurance, food stamps, Medicare and Medicaid, and many other programs.

Also very important is Congress's power to regulate foreign and domestic commerce. Since the earliest days of the republic, Congress has vigorously used the power to regulate foreign trade through tariffs, import quotas, and licenses and trade embargoes. Through its power to regulate domestic commerce, Congress has vastly expanded its powers to cope with national problems in areas never imagined by the framers of the Constitution.

The Constitution simply states that Congress shall have the power to regulate commerce with foreign countries “and among the several states.” This general and rather innocuous language gave Congress the latitude it needed, beginning in the 1880s, to expand its power over commerce to meet the needs of an increasingly industrialized and urbanized society linked by rapid transportation and communication. In the early and mid-nineteenth century the Supreme Court accepted congressional regulation of interstate commerce but viewed this power narrowly. It accepted regulation of common carriers, such as the railroads, but rejected regulation of private property rights, states' rights, and most businesses, as well as legislation concerning social evils, such as child labor.

Only in the late 1930s and 1940s did the Court embrace Congress's broad interpretation of interstate commerce to include business activity even where it had only an indirect effect on interstate commerce. The power was expanded further in the 1960s to deal with racial discrimination and other social problems and in the 1970s to encompass conservation and environmental issues.

Today congressional power in this area is practically limitless. Congress sets the rules conferring citizenship on foreign-born persons, and it regulates the admission into the country and the deportation of aliens. Congressional power extends to bankruptcy, patent and copyright issues, regulation of the U.S. currency, the right to set standard weights and measures, and authority to establish a national postal system.

Foreign Policy Powers

Congress most clearly shares its powers with the executive branch in the area of foreign affairs. The Constitution presupposes that the two branches will maintain a delicate balance in exercising their foreign policy prerogatives. Nonetheless, both branches still debate vigorously the scope of and limits on Congress's power in the formulation of U.S. foreign and defense policies. The extent of Congress's involvement in and influence over foreign policy has varied throughout American history. Since the early years of the Vietnam War in the 1960s, Congress and the White House have actively competed with each other for control of foreign policy.

Certain specific foreign policy powers granted to Congress are not disputed. These include the power to raise, support, and regulate the armed forces; the power to declare war and, through its power of the purse, to finance or withhold financing for U.S. participation in foreign wars; and the requirement that the Senate give its consent to all treaties and executive branch nominations of diplomatic officials. Although these powers have been important in ensuring that the legislative branch remains an independent force in U.S. foreign affairs, its role in some cases has been altered or diminished by international developments since World War I.

Probably the most important change is the erosion of the power of Congress to declare war. In the nuclear age, when decisions about war had to be made in minutes, not in days or weeks, the power of the national legislature to declare war seemed impractical. Presidents since World War II have committed U.S. armed forces without first asking Congress's consent. World War II was the last in which Congress exercised its power to declare war. Since then U.S. military forces have engaged in several major armed conflicts, including those in Korea and Vietnam.

In 1991, however, Congress—at the request of President George H. W. Bush—debated heatedly before approving a resolution authorizing the president to use force to evict invading Iraqi troops from Kuwait. In 2001 and 2002 his son, President George W. Bush, encountered few problems in convincing Congress to approve resolutions authorizing the use of force to respond to the September 11, 2001, terrorist attacks on the nation and to defend against the threat posed by Iraq.

Reacting to its inability to curtail or, ultimately, end U.S. involvement in the Vietnam War in the 1960s and early 1970s, Congress in 1973 enacted the War Powers Resolution over President Richard Nixon's veto. This measure was an effort by Congress to reinvigorate its war-making—or war-curtailing—power. But later presidents avoided its use, maintaining that it was an unconstitutional infringement on their powers. In battles with President Bill Clinton, some Republicans demanded advance congressional approval for U.S. deployment to Haiti and Bosnia and for any dispatch of combat forces under the United Nations flag. In 1993 some House Republicans invoked provisions of the war powers law, which they had long rejected as unconstitutional, to force expedited House action on a resolution that would have required U.S. forces to be withdrawn from Somalia more quickly than the administration had planned. In the end, Clinton survived a series of votes in the Senate over intervention abroad with his executive powers intact.

Congressional control of the purse strings also has not been effective in preventing U.S. armed intervention abroad. Once presidential decisions have been made to deploy U.S. military personnel overseas in hostile situations, it is difficult for Congress to force a halt to such operations, especially because doing so might jeopardize the lives of Americans stationed in those areas. Congress did, however, use the power of the purse to wind down the Vietnam War.

Another change in Congress's foreign policy powers was an increased reliance on executive agreements, which were compacts with other nations informally drawn up and agreed to by the executive branch alone, without any requirement for Senate consent. In certain areas of U.S. foreign policy, executive agreements largely replaced treaties.

Although some of Congress's formal constitutional powers in foreign affairs have decreased in importance, lawmakers' influence in this field has greatly expanded in other ways. Congressional backing is indispensable to the array of programs for foreign economic and military aid and international lending that the United States launched after World War II. These programs have expanded greatly since then, which gives Congress significant leverage over presidential policies. For example, when Congress approves such aid programs, it often writes laws giving itself a voice on how they are funded and administered and mandating what actions the White House can and cannot take.

Institutional Powers

Congress employs a wealth of institutional powers to buttress its position as an equal branch of government.

In the procedure for amending the Constitution, Congress and the states act alone; the president may propose constitutional amendments but has no formal role in their ratification. Article V provides that Congress, “whenever two-thirds of both Houses shall deem it necessary, shall propose” amendments to the Constitution, which take effect when ratified by three-fourths of the states. Alternatively, the states themselves, if two-thirds agree, can call a constitutional convention to propose amendments. The latter route, however, has never been used successfully.

The Senate alone possesses the key power to confirm or reject presidential appointments to many government positions. Most are confirmed routinely, but the few hundred top-level appointments requiring confirmation give the Senate a potent policy voice. Besides appointments at and beneath the cabinet level, the Senate's advice and consent power covers nominees for the Supreme Court and lower courts; for top-level diplomatic and military posts; and for federal regulatory agencies and boards.

The power to conduct investigations is not mentioned in the Constitution. It is an implied power, derived from the introductory clause in Article I declaring that “all legislative Powers herein granted shall be vested” in Congress. Investigations can cover the entire range of congressional activity. They are used to review the effectiveness of existing laws, to assess the need for new ones, and to probe into government waste, inefficiency, and corruption. While conducting investigations, chairs of committees sometimes use their subpoena power to compel reluctant witnesses to testify or provide information.

Questions about the right of Congress to investigate the executive branch emerged during an unprecedented lawsuit filed by the General Accounting Office, the investigative arm of Congress, against Vice President Richard Cheney, who was leading an executive branch task force on energy policy. The GAO sought to determine the costs of the task force's work and with whom Cheney's task force met as it wrote the administration's energy policy recommendations. A U.S. District Court judge dismissed the case in December 2002, saying in part that the GAO was not injured by the activities of the task force and therefore did not have standing to sue. However, the judge declined to decide the merits of whether the GAO should have the right to seek such information through lawsuits. “This case, in which neither a house of Congress nor any congressional committee has issued a subpoena for the disputed information or authorized this suit, is not the setting for such unprecedented judicial action,” said U.S. District Judge John Bates.

Congress is also charged with making the “Rules for the Government.” It can add or abolish federal agencies and departments and can even alter the size of the Supreme Court. The entire federal court structure was established by Congress. The power to admit new states into the Union also is conferred on Congress.

Several congressional powers directly affect the presidency. Congress is given the duty, now largely ceremonial, of counting the electoral votes for president and vice president after every election and formally announcing the winners. More important is the House's power to choose the president, and the Senate's power to choose the vice president, in the event that no candidate receives a clear majority of the vote.

The Twentieth and Twenty-fifth amendments also give Congress powers dealing with presidential disability and succession, including the power to confirm presidential choices to fill vacancies in the vice presidency. The House and Senate share the power to impeach the president and other officials and remove them from office for treason, bribery, or other “high crimes and misdemeanors.” Although rarely used, the impeachment power is perhaps Congress's most formidable weapon against the executive branch. The House draws up impeachment charges; the Senate acts as judge and jury.

Finally, the Constitution declares that Congress may “make all laws which shall be necessary and proper for carrying into Execution the foregoing Powers.” This catchall provision was originally intended to help Congress exercise the powers specifically enumerated in the Constitution. It was broadly defined by the Supreme Court in 1819 in the case of McCulloch v. Maryland. In practice, the provision has allowed Congress to extend its role and has led to far-reaching debates over the scope of congressional powers.

additional readings

Congressional Quarterly. Guide to Congress. 5th ed. Washington, D.C.: CQ Press, 2000.

Davidson, Roger H., and Walter J. Oleszek. Congress and Its Members. 8th ed. Washington, D.C.: CQ Press, 2002.

Jones, Charles O. Separate but Equal Branches: Congress and the Presidency. New York: Chatham House, 1999.

Josephy, Alvin M., Jr. On the Hill: A History of the American Congress. New York: Simon and Schuster, 1980.

Wilson, Woodrow. Congressional Government: A Study in American Politics. Boston: Houghton Mifflin, 1885. Reprint. Cleveland: Meridian Books, 1956.



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