Legislative Branch — Congress | The Three Branches

Origins

Born from a deadlock

At the 1787 Constitutional Convention, large and small states clashed over representation. The Virginia Plan (backed by Madison and Edmund Randolph) proposed a legislature apportioned by population — good for populous states. The New Jersey Plan (backed by William Paterson) proposed one vote per state — good for small ones. Connecticut delegates Roger Sherman and Oliver Ellsworth broke the deadlock in July 1787 with the Great Compromise: a two-chamber Congress, a House apportioned by population and a Senate with two seats per state regardless of size.

A second, darker compromise went into the same package: the Three-Fifths Compromise, under which enslaved people were counted as three-fifths of a person for both representation and direct taxation — inflating the political power of slaveholding states until the 13th and 14th Amendments (1865, 1868) made the clause obsolete.

The First Congress convened March 4, 1789, at Federal Hall in New York City. The House reached quorum and elected Pennsylvania's Frederick Muhlenberg as the first Speaker on April 1; the Senate followed on April 6 and immediately turned to counting the electoral votes that confirmed George Washington as president.

House vs. Senate

	House	Senate
Seats	435	100
Represents	Population, by district	Each state, equally
Term	2 years	6 years, staggered
Originally chosen by	Popular vote	State legislatures until 1913
Min. age	25	30
Presiding officer	Speaker of the House	Vice President

Article I, Section 8

Enumerated powers

The framers gave Congress the most explicit list of powers of any branch — and one clause elastic enough to stretch far past that list.

01
Tax & spendLay and collect taxes, duties, and excises; pay the nation's debts; provide for the common defense and general welfare.
02
Borrow & coin moneyBorrow on the credit of the United States; coin money and regulate its value; punish counterfeiting.
03
Regulate commerceThe Commerce Clause — regulate trade with foreign nations, among the states, and with tribal nations. The single most litigated grant of federal power in American history.
04
War powersDeclare war; raise and support armies (funding capped at two years at a time by the Constitution's own text); provide and maintain a navy.
05
Naturalization & bankruptcySet uniform rules for how immigrants become citizens and how bankruptcy is handled nationwide.
06
Post & patentsEstablish post offices and roads; grant patents and copyrights to "promote the progress of science and useful arts."
07
The Necessary and Proper ClauseMake all laws "necessary and proper" to carry out its other powers — the "elastic clause" that the Supreme Court used in McCulloch v. Maryland (1819) to uphold broad implied powers.
08
House-only: originate revenue billsAll bills raising revenue must start in the House — the chamber closest to the voters who'd pay the tax.
09
House-only: impeachmentThe House impeaches (formally charges) federal officials, including the President, by simple majority.
10
Senate-only: advice and consentConfirms presidential nominees (Cabinet, judges, ambassadors) by simple majority; ratifies treaties by two-thirds vote; tries impeachments, with a two-thirds vote required to convict and remove.

The process

How a bill becomes law

IntroductionA member introduces a bill in the House or Senate; it's assigned a number and referred to committee.
CommitteeThe relevant committee holds hearings, can amend the bill ("markup"), and votes whether to send it to the floor. Most bills die here.
Floor vote, first chamberDebated and voted on. In the Senate, ending debate on most legislation takes 60 votes to overcome a filibuster — a supermajority threshold found nowhere in the Constitution's text but deeply embedded in Senate rules.
Second chamberThe other chamber must pass an identical bill. If versions differ, a conference committee reconciles them.
The PresidentSign it into law; veto it and return it to Congress; or take no action — it becomes law automatically after 10 days (Sundays excluded) if Congress stays in session, or dies via "pocket veto" if Congress adjourns first.
OverrideCongress can override a veto with a two-thirds vote in both chambers — Congress's ultimate check on presidential rejection.

1789 → today

How Congress changed

1913 — 17th Amendment

Senators had been chosen by state legislatures since 1789. The Progressive Era amendment moved to direct popular election, responding to gridlocked state legislatures and corruption scandals.

1929 — Reapportionment Act

Fixed the House permanently at 435 seats, ending a century of growth that had tracked the population and westward expansion state by state.

1973 — War Powers Resolution

Passed over Nixon's veto after Vietnam. Requires the President to notify Congress within 48 hours of committing troops and limits deployments without a formal declaration of war.

1974 — Budget & Impoundment Control Act

Reasserted Congress's "power of the purse" after Nixon withheld (impounded) funds Congress had appropriated, and created the modern congressional budget process.

Who shaped it

Legislative branch, in brief

James Madison

1751–1836

Architect of the Virginia Plan and the Bill of Rights; later 4th President.

Henry Clay

1777–1852

"The Great Compromiser" — three terms as Speaker; brokered the Missouri Compromise.

Sam Rayburn

1882–1961

Longest-serving Speaker in history, guiding New Deal and postwar legislation.

Jeannette Rankin

1880–1973

First woman elected to Congress, in 1916 — four years before national suffrage.

LBJ

Lyndon B. Johnson

1908–1973

Senate Majority Leader famed for legislative dealmaking before the presidency.

Nancy Pelosi

b. 1940

First woman Speaker of the House (2007–2011, 2019–2023).

See the full roster →

The Legislative Branch — Congress