United States Senate

The drafters of the Constitution debated more about how to award representation in the Senate than about any other part of the Constitution. While bicameralism and the idea of a proportional "people's house" were widely popular, discussions about Senate representation proved contentious. In the end, some small states—unwilling to give up their equal power with larger states under the Articles of Confederation—threatened to secede in 1787, and won the day by a vote of 5–4 in what became known as the Connecticut Compromise. The Connecticut Compromise provided, among other things, that each state—regardless of population—would be represented by two senators.

First convened in 1789, the Senate of the United States was formed on the example of the ancient Roman Senate. The name is derived from the senatus, Latin for council of elders, derived from senex, meaning old man in Latin. Article Five of the Constitution stipulates that no constitutional amendment may be created to deprive a state of its equal suffrage in the Senate without that state's consent. The United States has had 50 states since 1959, thus the Senate has had 100 senators since 1959.

Before the adoption of the Seventeenth Amendment in 1913, senators were elected by the individual state legislatures. Problems with repeated vacant seats due to the inability of a legislature to elect senators, intrastate political struggles, bribery and intimidation gradually led to a growing movement to amend the Constitution to allow for the direct election of senators.

In contrast to the House of Representatives, the Senate has historically had stronger norms of conduct for its members.

Senate approval is required to pass any federal legislation. The Constitution provides several unique functions for the Senate that form its ability to "checks and balances" the powers of other elements of the federal government. These include the requirement that the Senate may advise and must consent to some of the president's government appointments; also, the Senate must consent to all treaties with foreign governments; it tries all impeachments, and it elects the vice president in the event no person gets a majority of the electoral votes.

Bills may be introduced in either chamber of Congress. However, the Constitution's Origination Clause provides that "All bills for raising Revenue shall originate in the House of Representatives". As a result, the Senate does not have the power to initiate bills imposing taxes. Furthermore, the House of Representatives holds that the Senate does not have the power to originate appropriation bills, or bills authorizing the expenditure of federal funds.

Historically, the Senate has disputed the interpretation advocated by the House. However, when the Senate originates an appropriations bill, the House simply refuses to consider it, thereby settling the dispute in practice. The constitutional provision barring the Senate from introducing revenue bills is based on the practice of the Parliament of the United Kingdom, in which money bills approved by Parliament have originated in the House of Commons per constitutional convention.

Although the Constitution gave the House the power to initiate revenue bills, in practice the Senate is equal to the House in the respect of spending. As Woodrow Wilson wrote:

The Senate's right to amend general appropriation bills has been allowed the widest possible scope. The upper house may add to them what it pleases; may go altogether outside of their original provisions and tack to them entirely new features of legislation, altering not only the amounts but even the objects of expenditure, and making out of the materials sent them by the popular chamber measures of an almost totally new character.

The approval of both houses is required for any bill, including a revenue bill, to become law. …

Article I, Section 3, of the Constitution, sets three qualifications for senators: (1) they must be at least 30 years old; (2) they must have been citizens of the United States for at least nine years; and (3) they must be inhabitants of the states they seek to represent at the time of their election. The age and citizenship qualifications for senators are more stringent than those for representatives. In Federalist No. 62, James Madison justified this arrangement by arguing that the "senatorial trust" called for a "greater extent of information and stability of character":

A senator must be thirty years of age at least; as a representative must be twenty-five. And the former must have been a citizen nine years; as seven years are required for the latter. The propriety of these distinctions is explained by the nature of the senatorial trust, which, requiring greater extent of information and stability of character, requires at the same time that the senator should have reached a period of life most likely to supply these advantages; and which, participating immediately in transactions with foreign nations, ought to be exercised by none who are not thoroughly weaned from the prepossessions and habits incident to foreign birth and education. The term of nine years appears to be a prudent mediocrity between a total exclusion of adopted citizens, whose merits and talents may claim a share in the public confidence, and an indiscriminate and hasty admission of them, which might create a channel for foreign influence on the national councils.

The Senate, not the judiciary, is the sole judge of a senator's qualifications. During its early years the Senate did not closely scrutinize the qualifications of its members. As a result, four senators who failed to meet the age requirement were admitted to the Senate: Henry Clay (aged 29 in 1806), John Jordan Crittenden (aged 29 in 1817), Armistead Thomson Mason (aged 28 in 1816), and John Eaton (aged 28 in 1818). Such an occurrence has not been repeated since.

In 1934, Rush D. Holt Sr. was elected to the Senate at the age of 29. He waited until he turned 30, on the next June 19, to take the oath of office. On November 7, 1972, Joe Biden was elected to the Senate at the age of 29, which was only 13 days prior to his 30th birthday on November 20, 1972. …

The "majority party" is the political party that either has a majority of seats or can form a coalition or caucus with a majority of seats; if two or more parties are tied, the vice president's affiliation determines which party is the majority party. The next-largest party is known as the minority party. The president pro tempore, committee chairs, and some other officials are generally from the majority party; they have counterparts (for instance, the "ranking members" of committees) in the minority party. Independents and members of third parties (so long as they do not caucus support either of the larger parties) are not considered in determining which is the majority party.

One hundred desks are arranged in the chamber in a semicircular pattern and are divided by a wide central aisle. The Democratic Party traditionally sits to the presiding officer's right, and the Republican Party traditionally sits to the presiding officer's left, regardless of which party has a majority of seats.

Each senator chooses a desk based on seniority within the party. By custom, the leader of each party sits in the front row along the center aisle. Forty-eight of the desks date back to 1819, when the Senate chamber was reconstructed after the original contents were destroyed in the 1812 Burning of Washington. Further desks of similar design were added as new states entered the Union. It is a tradition that each senator who uses a desk inscribes their name on the inside of the desk's drawer with a pen.

Except for the president of the Senate (who is the vice president), the Senate elects its own officers, who maintain order and decorum, manage and schedule the legislative and executive business of the Senate, and interpret the Senate's rules, practices and precedents. Many non-member officers are also hired to run various day-to-day functions of the Senate.

Under the Constitution, the vice president serves as president of the Senate. They may vote in the Senate (ex officio, for they are not an elected member of the Senate) in the case of a tie, but are not required to. For much of the nation's history the task of presiding over Senate sessions was one of the vice president's principal duties (the other being to receive from the states the tally of electoral ballots cast for president and vice president and to open the certificates "in the Presence of the Senate and House of Representatives", so that the total votes could be counted). Since the 1950s, vice presidents have presided over few Senate debates. Instead, they have usually presided only on ceremonial occasions, such as swearing in new senators, joint sessions, or at times to announce the result of significant legislation or nomination, or when a tie vote on an important issue is anticipated.

The Constitution authorizes the Senate to elect a president pro tempore (Latin for "president for a time"), who presides over the chamber in the vice president's absence and is, by custom, the senator of the majority party with the longest record of continuous service. Like the vice president, the president pro tempore does not normally preside over the Senate, but typically delegates the responsibility of presiding to a majority-party senator who presides over the Senate, usually in blocks of one hour on a rotating basis. Frequently, freshmen senators (newly elected members) are asked to preside so that they may become accustomed to the rules and procedures of the body. It is said that, "in practice they are usually mere mouthpieces for the Senate's parliamentarian, who whispers what they should do".

The presiding officer sits in a chair in the front of the Senate chamber. The powers of the presiding officer of the Senate are far less extensive than those of the speaker of the House. …