What does Congress do?

Congress makes federal laws, controls federal spending and taxation, regulates interstate and foreign commerce, declares war, and oversees the executive branch. These powers are listed in Article I, Section 8 of the Constitution, which sets out 18 specific clauses giving Congress authority over a wide range of national matters.

The first and most important power is lawmaking. Congress writes the federal statutes that govern everything from criminal penalties to immigration to environmental protection. Bills can originate in either chamber, with the exception of revenue-raising bills, which must start in the House of Representatives. Both chambers must pass a bill in identical form before it goes to the President.

The power of the purse is among the most consequential. Article I, Section 9 states that no money shall be drawn from the Treasury except through appropriations made by law. This means Congress controls every dollar the federal government spends, from the military budget to Social Security to highway construction. The annual appropriations process gives Congress significant leverage over executive agencies. Congress also has exclusive power to levy and collect federal taxes. The 16th Amendment, ratified in 1913, gave Congress the power to tax incomes without apportionment among the states, opening the door to the modern income tax system.

Other major powers include declaring war (Congress is the only branch that can formally declare war, though presidents have committed troops to combat many times without a declaration), regulating commerce among the states, coining money and setting its value, establishing post offices, granting patents and copyrights, raising and supporting armed forces, and creating federal courts beneath the Supreme Court. Congress also has oversight authority over executive agencies, conducted through hearings, subpoenas, and reporting requirements.

The Senate has special powers including ratifying treaties by a two-thirds vote, confirming presidential appointments to the Cabinet, federal courts, and other offices, and conducting impeachment trials. The House has the sole power to bring impeachment charges and to originate revenue bills. The necessary and proper clause at the end of Article I, Section 8 gives Congress authority to make laws that are necessary and proper for carrying out its enumerated powers, a flexible provision that has expanded congressional reach over time.