The Powers of Congress

Setting the Rules and Laying Down the Law

Woman walks on fountain near U.S. Capitol
Woman Walks on Fountain Near U.S. Capitol. Mark Wilson / Getty Images

Congress is one of three co-equal branches of the federal government, along with the judicial branch, represented by the courts, and the executive branch, represented by the presidency.

The powers of the United States Congress are set forth in Article I, Section 8 of the United States Constitution.

The constitutionally granted powers of Congress are further defined and interpreted by the rulings of the Supreme Court, and by its own rules, customs, and history.

The powers explicitly defined by the Constitution are called the “enumerated powers." Other powers not specifically listed in Section 8, but assumed to exist, are called “implied powers."

Not only does the Constitution define Congress' powers in relation to the judicial and executive branches, it also places limits on it concerning power delegated to the individual states.

Making Laws

Of all the powers of Congress, none is more important than its enumerated power to make laws.

Article I of the Constitution sets forth the powers of Congress in specific language. Section 8 states,

"Congress shall have Power … To make all Laws which shall be necessary and proper for carrying into Execution the foregoing Powers, and all other Powers vested by this Constitution in the Government of the United States, or in any Department or Officer thereof."

Laws aren't simply conjured out of thin air, of course. The legislative process is quite involved and designed to ensure proposed laws are given careful consideration. 

Any senator or representative may introduce a bill, after which it is referred to the appropriate legislative committee for hearings. The committee, in turn, debates the measure, possibly offering amendments, and then votes on it.

If approved, the bill heads back to the chamber from which it came, where the full body will vote on it. Assuming lawmakers approve the measure, it will be sent to the other chamber for a vote.

If the measure clears Congress, it is ready for the president's signature. But if each of the bodies approved differing legislation, it must be resolved in a joint congressional committee before being voted on again by both chambers.

The legislation then goes to the White House, where the president may either sign it into law or veto it. Congress, in turn, has the power to override a presidential veto with a two-thirds majority in both chambers.

Amending the Constitution

Congress has the power to amend the Constitution, though this is a long and arduous process.

Both chambers must approve the proposed constitutional amendment by a two-thirds majority, after which the measure is sent to the states. The amendment must then be approved by three-quarters of the state legislatures.

The Power of the Purse

Congress also has extensive powers over financial and budgetary issues. These include powers to:

  • Levy and collect taxes, duties, and excise fees
  • Allocate money to pay the government’s debts
  • Borrow money on the credit of the United States
  • Regulate commerce between the states and other nations
  • Coin and print money
  • Allocate money to provide for the common defense and general welfare of the United States

The Sixteenth Amendment, ratified in 1913, extended Congress’ power of taxation to include income taxes.

Its power of the purse is one of Congress' primary checks and balances on the actions of the executive branch.

Armed Forces

The power to raise and maintain armed forces is the responsibility of Congress, and it has the power to declare war. The Senate, but not the House of Representatives, has the power to approve treaties with foreign governments as well.

Congress has officially declared war on 11 occasions, including its first declaration of war with Great Britain in 1812. Congress approved its last formal declaration of war on December 8, 1941, against the Empire of Japan in response to that country's surprise attack on Pearl Harbor. Since World War II, Congress has agreed to resolutions authorizing the use of military force (AUMF) and continues to shape U.S. military policy through defense-related spending appropriations and oversight.

Historically, AUMFs have been far narrower in scope and much more limited than formal declarations of war, such as when Congress gave President John Adams clearance to protect American ships against French aggression in the Quasi-War of 1789 and Tripoli’s navy in 1802. 

More recently, however, AUMFs have become much broader, often granting presidents, under their authority as “Commander in Chief,” sweeping authority to deploy and engage America’s military around the world. In 1964, for example, as communist forces in Vietnam took increasingly militaristic actions against U.S. forces, Congress agreed to the Tonkin Gulf Resolution authorizing President Lyndon Johnson to “promote the maintenance of international peace and security in southeast Asia.” Although the concept of the AUMF has existed since the start of the Republic, the specific use of the term became commonplace in the 1990s during the Gulf War.

Other Powers and Duties

Congress has the power to establish post offices and maintain postal infrastructure. It also appropriates funds for the judicial branch. Congress can establish other agencies to keep the country running smoothly as well.

Bodies such as the Government Accountability Office and the National Mediation Board ensure the monetary appropriations and laws that Congress passes are applied properly.

Congress can investigate pressing national issues. For example, it held hearings in the 1970s to investigate the Watergate burglary that ultimately ended the presidency of Richard Nixon.

It is also charged with supervising and providing a balance for the executive and judicial branches.

Each house has exclusive duties as well. The House can initiate laws that require people to pay taxes and can decide whether public officials should be tried if accused of a crime.

Congressional representatives are elected to two-year terms, and the Speaker of the House is second in line to succeed the president after the vice president.

The Senate is responsible for confirming presidential appointments of Cabinet members, federal judges, and foreign ambassadors. The Senate also tries any federal official accused of a crime, once the House determines that a trial is in order.

Senators are elected to six-year terms; the vice president presides over the Senate and has the right to cast the deciding vote in the event of a tie.​

The Implied Powers of Congress

In addition to the explicit powers enumerated in Section 8 of the Constitution, Congress also has additional implied powers derived from the Necessary and Proper Clause of the Constitution, which permits it,

“To make all laws which shall be necessary and proper for carrying into execution the foregoing powers, and all other powers vested by this Constitution in the government of the United States, or in any department or officer thereof.”

Through the Supreme Court’s many interpretations of the Necessary and Proper Clause and the Commerce Clause—the enumerated power to regulate interstate commerce—such as McCulloch v Maryland, the true range of the lawmaking powers of Congress extends far beyond those enumerated in Section 8.

Updated by Robert Longley 

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Trethan, Phaedra. "The Powers of Congress." ThoughtCo, Apr. 5, 2023, Trethan, Phaedra. (2023, April 5). The Powers of Congress. Retrieved from Trethan, Phaedra. "The Powers of Congress." ThoughtCo. (accessed May 28, 2023).