President pro tempore of the United States Senate

The President pro tempore (also referred to as President pro tem) is the second-highest-ranking official of the United States Senate and the highest-ranking senator. The U.S. Constitution states the Vice President of the United States serves ex officio as President of the Senate, and is the highest-ranking official of the Senate even though he or she only votes in the case of a tie. During the Vice President's absence, the President pro tempore is the highest-ranking official in the Senate and may preside over its sessions. The President pro tempore is elected by the Senate and is customarily the most senior senator in the majority party. Normally, neither the Vice President of the United States nor the President pro tempore presides; instead, the duty is generally delegated to the majority party's junior senators to help them learn parliamentary procedure. The President pro tempore is third in the line of succession to the Presidency, after the Vice President of the United States and the Speaker of the House of Representatives.

The current President pro tempore of the Senate is Robert Byrd (D-West Virginia). By custom, the next Senators in line likely to be elected President pro tempore are Democrats Daniel Inouye of Hawaii and Patrick Leahy of Vermont. The senior members of the minority party are Republicans Dick Lugar of Indiana and Orrin Hatch of Utah.

Power and responsibilities
The President pro tempore is an office of the Senate mandated by Article I, section 3 of the Constitution. Although the position is in some ways equivalent to the Speaker of the House of Representatives, the powers of the President pro tempore are far more limited. In the Senate, most power rests with party leaders and individual senators, but as the chamber's presiding officer in the absence of the Vice President, the President pro tempore is authorized to perform certain duties, including ruling on points of order. Additionally, the President pro tempore is one of the two authorities to whom declarations of presidential inability or of ability to resume the presidency must be transmitted under the 25th Amendment to the Constitution (The Speaker of the House is the other.) The President pro tempore is third in the line of presidential succession, following the Vice President and the Speaker of the House. Additional duties include appointment of various Congressional officers, certain commissions, advisory boards, and committees and joint supervision of the congressional page school. The President pro tempore is the designed legal recipient of various reports to the Senate including War Power Act reports under which he or she, jointly with the Speaker, may have the President call Congress back into session. The officeholder is an ex officio member of various boards and commissions. With the Secretary and Sergeant at Arms of the Senate, the President pro tempore maintains order in the use of Senate buildings as per Senate rules.

History
The office of President pro tempore was established by the Constitution of the United States in 1789. The first President pro tempore was elected on April 6 the same year. Originally, the President pro tempore was appointed on a daily or weekly basis when the Vice President of the United States was not present to preside over the Senate. Until the 1960s, it was common practice for the Vice President to preside over daily Senate sessions, so the President pro tempore rarely presided over the Senate unless the Vice Presidency became vacant.

Until 1891, the President pro tempore only served until the return of the Vice President to the chair or the adjournment of a session of Congress. Between 1792 and 1886, the President pro tempore was second in the line of presidential succession following the Vice President and preceding the Speaker of the House of Representatives. When President Andrew Johnson, who had no Vice President, was impeached and tried in 1868, Senate President pro tempore Benjamin Franklin Wade was next in line to the Presidency. Wade's radicalism is thought by many historians to be a major reason why the Senate, which did not want to see Wade in the White House, acquitted Johnson. The President pro tempore and the Speaker were removed from the line of succession in 1886, but were restored in 1947. This time, however, the President pro tempore followed the Speaker of the House.

Following the resignation for health reasons of then-President pro tempore William P. Frye, a Congress divided among progressive Republicans, conservative Republicans, and Democrats reached a compromise by which each of their candidates would rotate holding the office from 1911 to 1913. (See Presidents pro tempore of the United States Senate, 1911-1913.)

Acting President pro tempore
While the President pro tempore technically does have official duties, the holders of the office have, like the Vice President, over time ceased presiding over the Senate on a daily basis, owing to the mundane nature of the position. Furthermore, as the President pro tempore is now usually the most senior senator of the majority party, he or she most likely also chairs a major Senate committee, along with other duties this status entails. Therefore, the President pro tempore has less time now than in the past to preside daily over the Senate. Instead, any junior senator can be designated acting President pro tempore to preside over the Senate on a daily basis. This allows junior senators to learn proper parliamentary procedure.

Permanent Acting President pro tempore
In June 1963, because of the illness of President pro tempore Carl Hayden, Senator Lee Metcalf was designated Permanent Acting President pro tempore. No term was imposed on this designation, so Metcalf retained it until he died in office in 1978.

Deputy President pro tempore
The ceremonial post of Deputy President pro tempore was created for Hubert Humphrey, a former Vice President of the United States, in 1977 following his losing bid to become the Senate majority leader. The Senate resolution creating the position stated that any former President of the United States or former Vice President of the United States serving in the United States Senate would be entitled to this position. Since Humphrey's death in 1978, no other former President or former Vice President has served in the Senate. As of 2009, if they successfully sought election to the Senate, five living Presidents, (Jimmy Carter, George H.W. Bush, Bill Clinton, George W. Bush, and Barack Obama) and five living Vice-Presidents, (Walter Mondale, Dan Quayle, Al Gore, Dick Cheney, and Joe Biden), are eligible for the position of Deputy President pro tempore. Former Vice-President Walter Mondale's failed 2002 Senate election bid is the only time this appeared to be a real possibility.

When the President pro tempore becomes unable to perform the duties of office for an extended period, the current practice is to elect a Senator as Deputy President pro tempore, as opposed to a Permanent Acting President pro tempore, to carry out the duties until the President pro tempore can resume the duties. George J. Mitchell was elected Deputy President pro tempore in 1987–1988, because of the illness of President pro tempore John C. Stennis. The office to date has remained vacant. Hubert Humphrey and George J. Mitchell are the only Senators to date that have held the title.

The post may be largely honorary and ceremonial, nevertheless, it comes with a salary. By statute, the compensation granted to the position holder equals the rate of annual compensation paid to the President pro tempore, Majority Leader, and Minority Leader. (See .)

President pro tempore emeritus
"President pro tempore emeritus" was an honorary title from June 2001 to January 2009, given to a member of the minority party in the United States Senate who had previously served as President pro tempore. Republican Ted Stevens was the last to hold the title. Stevens served as President pro tempore from 2003 to 2007.

Strom Thurmond of South Carolina was the first person elected President pro tempore emeritus, being elected when the Democratic Party regained a majority in the Senate in 2001. With the change in party control, Democrat Robert Byrd of West Virginia replaced Thurmond as President pro tempore, reclaiming a position he had previously held from 1989 to 1995 and again briefly earlier in 2001. Thurmond served as President pro tempore emeritus until his retirement from the Senate on January 3, 2003, which coincided with another party change (from Democratic to Republican control) making Byrd the second person to hold the position.

While the President pro tempore emeritus had no official duties, he was entitled to an increase in staff. The President pro tempore emeritus also worked closely with party leaders and advised them on the functions of the Senate.

A President pro tempore emeritus whose party regains the majority can also serve again as President pro tempore, as happened at the beginning of the 110th Congress on January 4, 2007. When party control changed from Republican to Democratic, Robert Byrd reclaimed the position of President pro tempore from Ted Stevens, who became the third President pro tempore emeritus.

Since Ted Stevens left the Senate on January 3, 2009, there has been no President pro tempore emeritus for the first time since the title's creation in 2001.

Salary
The salary of the President pro tempore for 2006 was $183,500, equal to that of the Majority Leader and Minority Leader of both Houses of Congress. The salary increased to $188,100 in January 2008. If there is a vacancy in the office of Vice President then the salary would be the same as the Vice-President, $221,000.

Higher offices
Only one former President pro tempore ever became President of the United States (John Tyler, who as Vice President succeeded William Henry Harrison in 1841).

Only three former Presidents pro tempore ever became Vice President of the United States: Tyler, William R. King and Charles Curtis.