United States Senate

The United States Senate is the upper house of the bicameral legislature of the United States, and together with the United States House of Representatives comprises the United States Congress. The composition and powers of the Senate are established in Article One of the U.S. Constitution (which does not use the terms "upper" and "lower"). Each U.S state is represented by two senators, regardless of population. Senators serve staggered six-year terms. The chamber of the United States Senate is located in the north wing of the Capitol, in Washington, D.C., the national capital. The House of Representatives convenes in the south wing of the same building.

The Senate has several exclusive powers not granted to the House, including consenting to treaties as a precondition to their ratification and consenting or confirmation of appointments of Cabinet secretaries, federal judges, other federal executive officials, military officers, regulatory officials, ambassadors, and other federal uniformed officers, as well as  trying federal officials impeached by the House. The Senate is both a more deliberative and more prestigious body than the House of Representatives, due to its longer terms, smaller size, and statewide constituencies, which historically led to a more collegial and less partisan atmosphere. The Senate is often described as the "world's greatest deliberative body".

History
The framers of the Constitution created a bicameral Congress primarily as a compromise between those who felt that each state, since it was sovereign, should be equally represented, and those who felt the Legislature must directly represent the People, as did the House of Commons in Britain. There was also a desire to have two Houses that could act as an internal check on each other. One was intended to be a "People's House" directly elected by the People, and with short terms obliging the representatives to remain close to their constituents. The other was intended to represent the states to such extent as they retained their sovereignties not expressly delegated to the national government. The Senate is thus not intended to represent the people of the United States equally. The Constitution provides that the approval of both chambers is necessary for the passage of legislation.

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 (from senex meaning old man in Latin).

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 District of Columbia and all other territories (including territories, protectorates, etc.) are not entitled to representation in either House of the Congress. The United States has had 50 states since 1959, thus the Senate has had 100 senators since 1959.

The disparity between the most and least populous states has grown since the Great Compromise, which granted each state equal representation in the Senate and a minimum of three presidential Electors, regardless of population. In 1787, Virginia had roughly 10 times the population of Rhode Island, whereas today California has roughly 70 times the population of Wyoming, based on the 1790 and 2000 censuses. Seats in the House of Representatives are apportioned by population.

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

Qualifications
Article I, Section 3 of the Constitution sets three qualifications for senators: 1) each senator must be at least 30 years old, 2) must have been a citizen of the United States for at least the past nine years, and 3) must be (at the time of the election) an inhabitant of the state he or she seeks to represent. 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."

The Senate (not the judiciary) is the sole judge of a senator's qualifications. During its early years, however, the Senate did not closely scrutinize the qualifications of members. As a result, three senators who failed to meet the age qualification were nevertheless admitted to the Senate: Henry Clay (aged 29 in 1806), and Armistead Thomson Mason (aged 28 in 1816) and John Eaton (aged 28 in 1818). Such an occurrence, however, 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 to take the oath of office. Likewise, Joe Biden was elected to the Senate shortly before his 30th birthday in 1972; he had passed his 30th birthday by the time the Senate conducted its swearing-in ceremony for that year's incoming senators in January 1973.

The Fourteenth Amendment to the United States Constitution disqualifies from the Senate federal or state officers who had taken the requisite oath to support the Constitution, but later engaged in rebellion or aided the enemies of the United States. This provision, which came into force soon after the end of the Civil War, was intended to prevent those who sided with the Confederacy from serving. That Amendment, however, also provides a method to remove that disqualification: a two-thirds vote of both chambers of Congress.

Elections and term
Originally, senators were selected by the state legislatures, not by popular elections. By the early years of the 20th century, the legislatures of as many as 29 states had provided for popular election of senators by referendums. Popular election to the Senate was standardized nationally in 1913 by the ratification of the 17th Amendment.

Term
Senators serve terms of six years each; the terms are staggered so that approximately one-third of the seats are up for election every two years. This was achieved by dividing the senators of the 1st Congress into thirds (called classes), where the terms of one-third expired after two years, the terms of another third expired after four, and the terms of the last third expired after six years. This arrangement is also implemented following the admission of new states into the union. The staggering of terms has been arranged such that both seats from a given state are not contested in the same general election, except when a mid-term vacancy is being filled. Current senators whose six-year terms will expire on January 3, 2011, belong to Class III.

A member who has been elected, but not yet seated, is called a "senator-elect"; a member who has been appointed to a seat, but not yet seated, is called a "senator-designate".

Elections
Elections to the Senate are held on the first Tuesday after the first Monday in November in even-numbered years, Election Day, and coincide with elections for the House of Representatives. Senators are elected by their state as a whole. In most states (since 1970), a primary election is held first for the Republican and Democratic parties, with the general election following a few months later. Ballot access rules for independent and minor party candidates vary from state to state. The winner is the candidate who receives a plurality of the popular vote. In some states, runoffs are held if no candidate wins a majority.

Mid-term vacancies
The Seventeenth Amendment allows governors, with the approval of their legislature, to appoint temporary senators until either a special or regular election takes place. The official wording provides that "the legislature of any State may empower the executive thereof to make temporary appointments until the people fill the vacancies by election as the legislature may direct." Some states, as stated above, provide for a special election to fill a Senate vacancy. A special election need not be held immediately after the vacancy arises; often, it may wait until the next biennial congressional election. If a special election for one seat happens to coincide with a general election for the state's other seat, then the two elections are not combined, but are instead contested separately. A senator elected in a special election serves until the original six-year term expires, not for a full term.

Forty-six states permit governors to make Senate appointments of varying lengths as of 2009. Oregon and Wisconsin require special elections for vacancies, and Oklahoma permits the governor to appoint only the winner of a special election. In September 2009, Massachusetts changed its law to enable the governor to appoint a temporary replacement for the late Senator Kennedy until the special election in January 2010. In 2004, Alaska enacted legislation and a separate ballot referendum that took effect on the same day, but that conflicted with each other. The effect of the ballot-approved law is to withhold from the governor authority to appoint a senator. Because the 17th Amendment vests the power to grant that authority to the legislature — not the people or the state generally — it is unclear whether the ballot measure supplants the legislature's statute granting that authority. As a result, it is uncertain whether an Alaska governor may appoint an interim senator to serve until a special election is held to fill the vacancy.

In 2009, Wisconsin Democratic Senator Russ Feingold announced he would introduce a bill proposing a constitutional amendment to require Senate vacancies be filled by special elections, as the Constitution already requires for vacancies in the House of Representatives.

Oath
The Constitution requires that senators take an oath or affirmation to support the Constitution. Congress has prescribed the following oath for new senators: I, A— B—, do solemnly swear (or affirm) that I will support and defend the Constitution of the United States against all enemies, foreign and domestic; that I will bear true faith and allegiance to the same; that I take this obligation freely, without any mental reservation or purpose of evasion; and that I will well and faithfully discharge the duties of the office on which I am about to enter. So help me God.

Salary and benefits
The annual salary of each senator, as of 2009, is $174,000; the president pro tempore and party leaders receive $193,400. In June 2003, at least 40 of the then-senators were millionaires.

Along with earning salaries, senators receive retirement and health benefits that are identical to other federal employees, and are fully vested after five years of service. Senators are covered by the Federal Employees Retirement System (FERS) or Civil Service Retirement System (CSRS). As it is for federal employees, congressional retirement is funded through taxes and the participants' contributions. Under FERS, senators contribute 1.3% of their salary into the FERS retirement plan and pay 6.2% of their salary in Social Security taxes. The amount of a senator's pension depends on the years of service and the average of the highest 3 years of their salary. The starting amount of a senator's retirement annuity may not exceed 80% of their final salary. In 2006, the average annual pension for retired senators and representatives under CSRS was $60,972, while those who retired under FERS, or in combination with CSRS, was $35,952.

Political prominence
Senators are regarded as more prominent political figures than members of the House of Representatives because there are fewer of them, and because they serve for longer terms, usually represent larger constituencies (the exception being House at-large districts, which similarly comprise entire states), sit on more committees, and have more staffers. Far more senators have been nominees for the presidency than representatives. Furthermore, three senators (Warren Harding, John Kennedy, and Barack Obama) have been elected president while serving in the Senate, while only one Representative (James Garfield) has been elected president while serving in the House. Recent criticisms of the Senate's operations point to obsolescence as a result of partisan paralysis and a preponderance of arcane rules.

Seniority
According to the convention of Senate seniority, the senator with the longer tenure in each state is known as the "senior senator"; the other is the "junior senator". This convention, however, does not have official significance, though it is a factor in the selection of physical offices. In the 111th Congress, the most-senior "junior senator" is Tom Harkin of Iowa, who was sworn in on January 3, 1985 and is currently 14th in seniority. The most-junior "senior senator" is Mark Udall of Colorado, who was sworn in on January 3, 2009—just two weeks before the state's junior senator, Michael Bennet – and is currently 85th in seniority.

Expulsion and other disciplinary actions
The Senate may expel a senator by a two-thirds vote. Fifteen senators have been expelled in the history of the Senate: William Blount, for treason, in 1797, and fourteen in 1861 and 1862 for supporting the Confederate secession. Although no senator has been expelled since 1862, many senators have chosen to resign when faced with expulsion proceedings—for example, Bob Packwood in 1995. The Senate has also censured and condemned senators; censure requires only a simple majority and does not remove a senator from office. Some senators have opted to withdraw from their re-election races rather than face certain censure or expulsion, such as Robert Torricelli in 2002.

Majority and minority parties
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 with or support either of the larger parties) are not considered in determining which is the majority party.

Seating
The Democratic Party always sits to the presiding officer's right, and the Republican party always sits to the presiding officer's left, regardless which party has a majority of seats. In this respect, the Senate differs from the British House of Commons and other parliamentary bodies in the British Commonwealth of Nations and elsewhere.

Officers
The Vice President of the United States presides over the Senate, but the party leaders have the real power and they control procedure. Many non-member officers are also hired to run the day-to-day functions of the Senate.

Presiding over the Senate
The Vice President of the United States is the ex officio President of the Senate, with authority to preside over the Senate's sessions, although he can vote only to break a tie. For decades the task of presiding over Senate sessions was one of the vice president's principal duties. Since the 1950s, vice presidents have presided over few Senate debates. Instead, they have usually presided only on ceremonial occasions, such as joint sessions, or at times 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") to preside in the vice president's absence; the most senior senator of the majority party is customarily chosen to serve in this position. Like the vice president, the president pro tempore does not normally preside over the Senate, but typically delegates the responsibility of presiding to junior senators of the majority party, 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.

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. The presiding officer calls on senators to speak (by the rules of the Senate, the first senator who rises is recognized); ruling on points of order (objections by senators that a rule has been breached, subject to appeal to the whole chamber); and announcing the results of votes.

Party leaders
Each party elects Senate party leaders. Floor leaders act as the party chief spokespeople. The Senate Majority Leader is responsible for controlling the agenda of the chamber by scheduling debates and votes. Each party elects a whip who works to ensure that their party's senators vote as the party leadership desires.

Non-member officers
The Senate is served by several officials who are not members. The Senate's chief administrative officer is the Secretary of the Senate, who maintains public records, disburses salaries, monitors the acquisition of stationery and supplies, and oversees clerks. The Assistant Secretary of the Senate aids the secretary in their work. Another official is the Sergeant at Arms, who, as the Senate's chief law enforcement officer, maintains order and security on the Senate premises. The Capitol Police handles routine police work, with the sergeant at arms primarily responsible for general oversight. Other employees include the Chaplain, who is elected by the Senate, and Pages, who are appointed.

Daily sessions
The Senate uses Standing Rules of the Senate for operation. Like the House of Representatives, the Senate meets in the United States Capitol in Washington, D.C. At one end of the chamber of the Senate is a dais from which the presiding officer presides. The lower tier of the dais is used by clerks and other officials. One hundred desks are arranged in the chamber in a semicircular pattern and are divided by a wide central aisle. By tradition, Republicans sit to the right of the center aisle and Democrats to the left, facing the presiding officer. Each senator chooses a desk based on seniority within and party. By custom, the leader of each party sits in the front row along the center aisle. Sessions of the Senate are opened with a special prayer or invocation and typically convene on weekdays. Sessions of the Senate are generally open to the public and are broadcast live on television, usually by C-SPAN 2.

Senate procedure depends not only on the rules, but also on a variety of customs and traditions. The Senate commonly waives some of its stricter rules by unanimous consent. Unanimous consent agreements are typically negotiated beforehand by party leaders. A senator may block such an agreement, but in practice, objections are rare. The presiding officer enforces the rules of the Senate, and may warn members who deviate from them. The presiding officer sometimes uses the gavel of the Senate to maintain order.

A "hold" is placed when the leader's office is notified that a senator intends to object to a request for unanimous consent from the Senate to consider or pass a measure. A hold may be placed for any reason and can be lifted by a senator at any time. A senator may place a hold simply to review a bill, to negotiate changes to the bill, or to kill the bill. A bill can be held for as long as the senator who objects to the bill wishes to block its consideration.

Holds can be overcome, but require time-consuming procedures such as filing cloture. Holds are considered private communications between a senator and the Leader, and are sometimes referred to as "secret holds." A senator may disclose that he or she has placed a hold.

The Constitution provides that a majority of the Senate constitutes a quorum to do business. Under the rules and customs of the Senate, a quorum is always assumed present unless a quorum call explicitly demonstrates otherwise. A senator may request a quorum call by "suggesting the absence of a quorum"; a clerk then calls the roll of the Senate and notes which members are present. In practice, senators rarely request quorum calls to establish the presence of a quorum. Instead, quorum calls are generally used to temporarily delay proceedings; usually such delays are used while waiting for a senator to reach the floor to speak or to give leaders time to negotiate. Once the need for a delay has ended, a senator may request unanimous consent to rescind the quorum call.

Debate
During debates, senators may only speak if called upon by the presiding officer, but the presiding officer is required to recognize the first senator who rises to speak. Thus, the presiding officer has little control over the course of debate. Customarily, the Majority Leader and Minority Leader are accorded priority during debates even if another senator rises first. All speeches must be addressed to the presiding officer, who is addressed as "Mr. President" or "Madam President", and not to another member; other Members must be referred to in the third person. In most cases, senators do not refer to each other by name, but by state or position, using forms such as "the senior senator from Virginia", "the gentlewoman from California", or "my distinguished friend the Chairman of the Judiciary Committee". Senators address the Senate standing next to their desk.

Apart from rules governing civility, there are few restrictions on the content of speeches; there is no requirement that speeches be germane to the matter before the Senate.

The rules of the Senate provide that no senator may make more than two speeches on a motion or bill on the same legislative day. A legislative day begins when the Senate convenes and ends with adjournment; hence, it does not necessarily coincide with the calendar day. The length of these speeches is not limited by the rules; thus, in most cases, senators may speak for as long as they please. Often, the Senate adopts unanimous consent agreements imposing time limits. In other cases (for example, for the budget process), limits are imposed by statute. However, the right to unlimited debate is generally preserved.

Filibuster and cloture
The filibuster is a tactic used to defeat bills and motions by prolonging debate indefinitely. A filibuster may entail long speeches, dilatory motions, and an extensive series of proposed amendments. The Senate may end a filibuster by invoking cloture. In most cases, cloture requires the support of three-fifths of the Senate; however, if the matter before the Senate involves changing the rules of the body—this includes amending provisions regarding the filibuster—a two-thirds majority is required. In current practice, the threat of filibuster is more important than its use; almost any motion that does not have the support of three-fifths of the Senate effectively fails. Historically, cloture has rarely been invoked because bipartisan support is usually necessary to obtain the required supermajority, so a bill that already has bipartisan support is rarely subject to threats of filibuster. However, motions for cloture have increased significantly in recent years.

If the Senate invokes cloture, debate does not end immediately; instead, it is limited to 30 additional hours unless increased by another three-fifths vote. The longest filibuster speech in the history of the Senate was delivered by Strom Thurmond, who spoke for over 24 hours in an unsuccessful attempt to block the passage of the Civil Rights Act of 1957.

Under certain circumstances, the Congressional Budget Act of 1974 provides for a process called "reconciliation" by which Congress can pass bills related to the budget without those bills being subject to a filibuster. This is accomplished by limiting all Senate floor debate to 20 hours.

Voting
When debate concludes, the motion in question is put to a vote. The Senate often votes by voice vote. The presiding officer puts the question, and Members respond either "Aye" (in favor of the motion) or "No" (against the motion). The presiding officer then announces the result of the voice vote. A senator, however, may challenge the presiding officer's assessment and request a recorded vote. The request may be granted only if it is seconded by one-fifth of the senators present. In practice, however, senators second requests for recorded votes as a matter of courtesy. When a recorded vote is held, the clerk calls the roll of the Senate in alphabetical order; senators respond when their name is called. Senators who were not in the chamber when their name was called may still cast a vote so long as the voting remains open. The vote is closed at the discretion of the presiding officer, but must remain open for a minimum of 15 minutes. If the vote is tied, the vice president, if present, is entitled to a casting vote. If the vice president is not present, the motion fails.

Closed session
On occasion, the Senate may go into what is called a secret or closed session. During a closed session, the chamber doors are closed, cameras are turned off, and the galleries are completely cleared of anyone not sworn to secrecy, not instructed in the rules of the closed session, or not essential to the session. Closed sessions are rare and usually held only when the Senate is discussing sensitive subject matter such as information critical to national security, private communications from the president, or deliberations during impeachment trials. A senator may call for and force a closed session if the motion is seconded by at least one other member, but an agreement usually occurs beforehand. If the Senate does not approve release of a secret transcript, the transcript is stored in the Office of Senate Security and ultimately sent to the national archives. The proceedings remain sealed indefinitely until the Senate votes to remove the injunction of secrecy.

Calendars
The Senate maintains a Senate Calendar and an Executive Calendar. The former identifies bills and resolutions awaiting Senate floor actions. The latter identifies executive resolutions, treaties, and nominations reported out by Senate committee(s) and awaiting Senate floor action. Both are updated each day the Senate is in session.

Committees



 * See List of United States Senate committees for the full list.

The Senate uses committees (and their subcommittees) for a variety of purposes, including the review of bills and the oversight of the executive branch. Formally, the whole Senate appoints committee members. In practice, however, the choice of members is made by the political parties. Generally, each party honors the preferences of individual senators, giving priority based on seniority. Each party is allocated seats on committees in proportion to its overall strength.

Most committee work is performed by 16 standing committees, each of which has jurisdiction over a field such as finance or foreign relations. Each standing committee may consider, amend, and report bills that fall under its jurisdiction. Furthermore, each standing committee considers presidential nominations to offices related to its jurisdiction. (For instance, the Judiciary Committee considers nominees for judgeships, and the Foreign Relations Committee considers nominees for positions in the Department of State.) Committees may block nominees and impede bills from reaching the floor of the Senate. Standing committees also oversee the departments and agencies of the executive branch. In discharging their duties, standing committees have the power to hold hearings and to subpoena witnesses and evidence.

The Senate also has several committees that are not considered standing committees. Such bodies are generally known as select or special committees; examples include the Select Committee on Ethics and the Special Committee on Aging. Legislation is referred to some of these committees, although the bulk of legislative work is performed by the standing committees. Committees may be established on an ad hoc basis for specific purposes; for instance, the Senate Watergate Committee was a special committee created to investigate the Watergate scandal. Such temporary committees cease to exist after fulfilling their tasks.

The Congress includes joint committees, which include members from both the Senate and the House of Representatives. Some joint committees oversee independent government bodies; for instance, the Joint Committee on the Library oversees the Library of Congress. Other joint committees serve to make advisory reports; for example, there exists a Joint Committee on Taxation. Bills and nominees are not referred to joint committees. Hence, the power of joint committees is considerably lower than those of standing committees.

Each Senate committee and subcommittee is led by a chair (usually a member of the majority party). Formerly, committee chairs were determined purely by seniority; as a result, several elderly senators continued to serve as chair despite severe physical infirmity or even senility. committee chairs are elected, but, in practice, seniority is rarely bypassed. The chairs hold extensive powers: they control the committee's agenda, and so decide how much, if any, time to devote to the consideration of a bill; they act with the power of the committee in disapproving or delaying a bill or a nomination by the president; they manage on the floor of the full Senate the consideration of those bills the committee reports. This last role was particularly important in mid-century, when floor amendments were thought not to be collegial. They also have considerable influence: senator who cooperate with their committee chairs are likely to accomplish more good for their states than those who do not. The Senate rules and customs were reformed in the twentieth century, largely in the 1970s. Committee chairmen have less power and are generally more moderate and collegial in exercising it, than they were before reform. The second-highest member, the spokesperson on the committee for the minority party, is known in most cases as the ranking member. In the Select Committee on Intelligence and the Select Committee on Ethics, however, the senior minority member is known as the vice chair.

Legislative functions
Bills may be introduced in either House of Congress. However, the Constitution 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 British Parliament, in which only the House of Commons may originate such measures.

Although the Constitution gave the House the power to initiate revenue bills, in practice the Senate is equal to the House in the respects of taxation and 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. Both Houses must pass the same version of the bill; if there are differences, they may be resolved by sending amendments back and forth or by a conference committee, which includes members of both bodies.

Checks and balances
The Constitution provides several unique functions for the Senate that form its ability to "check and balance" 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 ratify 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.

The president can make certain appointments only with the advice and consent of the Senate. Officials whose appointments require the Senate's approval include members of the Cabinet, heads of most federal executive agencies, ambassadors, Justices of the Supreme Court, and other federal judges. Under Article II, Section 2 of the Constitution, a large number of government appointments are subject to potential confirmation; however, Congress has passed legislation to authorize the appointment of many officials without the Senate's consent (usually, confirmation requirements are reserved for those officials with the most significant final decision-making authority). Typically, a nominee is first subject to a hearing before a Senate committee. Thereafter, the nomination is considered by the full Senate. The majority of nominees are confirmed, but in a small number of cases each year, Senate Committees will purposely fail to act on a nomination to block it. In addition, the president sometimes withdraws nominations when they appear unlikely to be confirmed. Because of this, outright rejections of nominees on the Senate floor are infrequent (there have been only nine Cabinet nominees rejected outright in the history of the United States).

The powers of the Senate concerning nominations are, however, subject to some constraints. For instance, the Constitution provides that the president may make an appointment during a congressional recess without the Senate's advice and consent. The recess appointment remains valid only temporarily; the office becomes vacant again at the end of the next congressional session. Nevertheless, presidents have frequently used recess appointments to circumvent the possibility that the Senate may reject the nominee. Furthermore, as the Supreme Court held in Myers v. United States, although the Senate's advice and consent is required for the appointment of certain executive branch officials, it is not necessary for their removal.

The Senate also has a role in ratifying treaties. The Constitution provides that the president may only ratify a treaty if two-thirds of the senators vote to grant advice and consent. However, not all international agreements are considered treaties under US domestic law, even if they are considered treaties under international law. Congress has passed laws authorizing the president to conclude executive agreements without action by the Senate. Similarly, the president may make congressional-executive agreements with the approval of a simple majority in each House of Congress, rather than a two-thirds majority in the Senate. Neither executive agreements nor congressional-executive agreements are mentioned in the Constitution, leading some scholars such as Laurence Tribe and John Yoo to suggest that they unconstitutionally circumvent the treaty-ratification process. However, courts have upheld the validity of such agreements.

The Constitution empowers the House of Representatives to impeach federal officials for "Treason, Bribery, or other high Crimes and Misdemeanors" and empowers the Senate to try such impeachments. If the sitting President of the United States is being tried, the Chief Justice of the United States presides over the trial. During an impeachment trial, senators are constitutionally required to sit on oath or affirmation. Conviction requires a two-thirds majority of the senators present. A convicted official is automatically removed from office; in addition, the Senate may stipulate that the defendant be banned from holding office. No further punishment is permitted during the impeachment proceedings; however, the party may face criminal penalties in a normal court of law.

In the history of the United States, the House of Representatives has impeached sixteen officials, of whom seven were convicted. (One resigned before the Senate could complete the trial.) Only two presidents of the United States have ever been impeached: Andrew Johnson in 1868 and Bill Clinton in 1998. Both trials ended in acquittal; in Johnson's case, the Senate fell one vote short of the two-thirds majority required for conviction.

Under the Twelfth Amendment, the Senate has the power to elect the vice president if no vice presidential candidate receives a majority of votes in the Electoral College. The Twelfth Amendment requires the Senate to choose from the two candidates with the highest numbers of electoral votes. Electoral College deadlocks are rare. In the history of the United States, the Senate has only broke a deadlock once. In 1837, it elected Richard Mentor Johnson. The House elects the president if the Electoral College deadlocks on that choice.

Current party standings
The party composition of the Senate as of July 16, 2010:

Official Senate histories
The following are published by the Senate Historical Office.
 * Biographical Directory of the United States Congress, 1774–1989
 * Robert Byrd. The Senate, 1789–1989. Four volumes.
 * Vol. I, a chronological series of addresses on the history of the Senate
 * Vol. II, a topical series of addresses on various aspects of the Senate's operation and powers
 * Vol. III, Classic Speeches, 1830–1993
 * Vol. IV, Historical Statistics, 1789–1992
 * Dole, Bob. Historical Almanac of the United States Senate
 * Hatfield, Mark O., with the Senate Historical Office. Vice Presidents of the United States, 1789–1993 (essays reprinted online)
 * Frumin, Alan S. Riddick's Senate Procedure. Washington, D.C.: Government Printing Office, 1992.

Miscellaneous

 * Baker, Richard A. The Senate of the United States: A Bicentennial History Krieger, 1988.
 * Baker, Richard A., ed., First Among Equals: Outstanding Senate Leaders of the Twentieth Century Congressional Quarterly, 1991.
 * Barone, Michael, and Grant Ujifusa, The Almanac of American Politics 1976: The Senators, the Representatives and the Governors: Their Records and Election Results, Their States and Districts (1975); new edition every 2 years
 * David W. Brady and Mathew D. McCubbins. Party, Process, and Political Change in Congress: New Perspectives on the History of Congress (2002)
 * Caro, Robert A. The Years of Lyndon Johnson. Vol. 3: Master of the Senate. Knopf, 2002.
 * Comiskey, Michael. Seeking Justices: The Judging of Supreme Court Nominees U. Press of Kansas, 2004.
 * Congressional Quarterly  Congress and the Nation: 2001–2004: A Review of Government and Politics: 107th and 108th Congresses  (2005); massive, highly detailed summary of Congressional activity, as well as major executive and judicial decisions; based on Congressional Quarterly Weekly Report and the annual CQ almanac.
 * Congressional Quarterly, Congress and the Nation: 1997–2001  (2002)
 * Congressional Quarterly. Congress and the Nation: 1993–1996  (1998)
 * Congressional Quarterly, Congress and the Nation: 1989–1992  (1993)
 * Congressional Quarterly, Congress and the Nation: 1985–1988  (1989)
 * Congressional Quarterly, Congress and the Nation: 1981–1984  (1985)
 * Congressional Quarterly, Congress and the Nation: 1977–1980  (1981)
 * Congressional Quarterly, Congress and the Nation: 1973–1976  (1977)
 * Congressional Quarterly, Congress and the Nation: 1969–1972  (1973)
 * Congressional Quarterly, Congress and the Nation: 1965–1968  (1969)
 * Congressional Quarterly, Congress and the Nation: 1945–1964  (1965), the first of the series
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