The Senate definition is straightforward: the Senate is the upper chamber of the United States Congress, made up of 100 members, two from each of the 50 states, who serve six-year terms and hold exclusive constitutional powers over treaties, presidential nominations, and impeachment trials. Its name traces to the Latin senex, meaning “elder,” and it operates alongside the House of Representatives as one of two chambers that must agree before a bill can become law.
Who Serves in the Senate
Every state sends exactly two senators to Washington, regardless of size. Wyoming’s roughly 580,000 residents have the same Senate representation as California’s nearly 39 million. That equal representation was a deliberate concession to smaller states at the Constitutional Convention, and Article V of the Constitution specifically prohibits stripping a state of its equal Senate representation without that state’s consent.
To serve, a person must be at least 30 years old, have been a U.S. citizen for at least nine years, and live in the state they represent at the time of election. Those requirements come from Article I, Section 3, Clause 3, and they are stricter than the House’s, which set the age at 25 and citizenship at seven years.1Constitution Annotated. ArtI.S3.C3.1 Overview of Senate Qualifications Clause
How Senators Are Elected
Voters elect senators directly. That has been true since the ratification of the 17th Amendment on April 8, 1913; before then, state legislatures chose senators.2National Archives. 17th Amendment to the U.S. Constitution: Direct Election of U.S. Senators (1913)
When a seat opens mid-term because of death, resignation, or expulsion, the 17th Amendment allows state legislatures to authorize the governor to appoint a temporary replacement. Rules vary by state. Some require the appointee to belong to the same party as the departing senator; others mandate a special election instead of a gubernatorial appointment.3U.S. Senate. Appointed Senators
Six-Year Terms and Staggered Elections
Senators serve six years, three times the length of a House term. Article I, Section 3, Clause 2 divides the chamber into three classes, so only about one-third of seats are up for election every two years.4Constitution Annotated. Article I Section 3 Clause 2 The Senate never turns over all at once. Even after a wave election, two-thirds of senators remain in place, which is why the chamber’s rules, precedents, and ongoing business tend to move slowly.
What the Senate Uniquely Does
The Constitution gives the Senate three powers that the House does not share.
Confirming Presidential Nominees
Article II, Section 2 gives the president the power to appoint cabinet secretaries, federal judges, ambassadors, and other senior officials “by and with the Advice and Consent of the Senate.”5Constitution Annotated. Article II Section 2 Clause 2 – Advice and Consent The Senate Judiciary Committee and other relevant committees vet nominees through hearings before the full Senate votes. A simple majority confirms or rejects a nomination. That threshold became uniform after the Senate eliminated the 60-vote filibuster requirement for most executive and judicial nominees in 2013 and extended the change to Supreme Court nominations in 2017.
Approving Treaties
The Senate votes on a resolution of ratification for treaties the president negotiates. If two-thirds of senators present approve, the president then formally ratifies the treaty by signing and exchanging the instruments of ratification with the other country.6Constitution Annotated. ArtII.S2.C2.1.1 Overview of President’s Treaty-Making Power The two-thirds requirement is one of the hardest thresholds in American government, which is one reason presidents increasingly use executive agreements that bypass the treaty process.
Conducting Impeachment Trials
The House has the sole power to impeach a federal official, meaning it brings the charges. The Senate has the sole power to conduct the trial. Article I, Section 3, Clause 6 requires a two-thirds vote of members present to convict, and conviction results in immediate removal from office.7Constitution Annotated. Article I Section 3 Clause 6 – Impeachment Trials When a president is on trial, the Chief Justice of the United States presides rather than the Vice President. Convictions are rare because the supermajority requirement demands support that crosses party lines.
Leadership Inside the Chamber
The Constitution names the Vice President of the United States as President of the Senate, but with a narrow role: no regular vote, and a ballot only to break a tie.8Constitution Annotated. Article I Section 3 Clause 4 Day-to-day presiding falls to the president pro tempore, whom the Senate elects from its own members. By tradition, that role goes to the longest-serving senator of the majority party.9U.S. Senate. About the President Pro Tempore
The positions that actually drive Senate business are the majority and minority leaders. Neither appears in the Constitution; both were formalized through chamber tradition and party organization in the 20th century.10U.S. Senate. Floor Leaders Receive Priority Recognition The majority leader schedules floor votes, calls bills from the calendar, and shapes the unanimous consent agreements that set debate time. A longstanding precedent gives the majority leader priority of recognition from the presiding officer, meaning the majority leader speaks and offers amendments before any other senator.11U.S. Senate. About Parties and Leadership – Majority and Minority Leaders
Committees
The Senate divides its workload among 20 permanent standing committees covering areas like armed services, finance, judiciary, and foreign relations.12U.S. Senate. Committees Most legislation never reaches the floor without first passing through the relevant committee, which holds hearings, takes public testimony, marks up the bill with amendments, and votes on whether to send it forward. Committees also conduct oversight investigations of federal agencies, subpoena witnesses, and review presidential nominees within their jurisdiction. A committee chair’s decision to schedule or ignore a bill often matters more than any floor speech.
The Filibuster and Cloture
The Senate allows senators to hold the floor and speak at length on any measure, unlike the House, which strictly limits debate. That tradition is the basis of the filibuster, where one or more senators delay or block a vote by continuing debate. Ending a filibuster requires invoking cloture, which since 1975 takes 60 out of 100 votes.13U.S. Senate. About Filibusters and Cloture
The 60-vote threshold means the majority party almost always needs support from at least some members of the minority to advance legislation. One major workaround is the budget reconciliation process, which limits debate and requires only a simple majority, but reconciliation bills must relate to spending, revenue, or the debt limit.
Discipline of Members
Article I, Section 5 gives the Senate the power to punish members for disorderly behavior and, with a two-thirds vote, to expel a member entirely.14Constitution Annotated. Article I Section 5 Short of expulsion, the Senate can censure a member by simple majority vote, a formal condemnation that carries no removal but significant political consequences. Fifteen senators have been expelled in the chamber’s history, most of them during the Civil War for supporting the Confederacy.15U.S. Senate. About Expulsion