Chapter 1: President Pro Tempore
Chapter 2: Constitutional Authority
Chapter 3: Presidential Succession
Chapter 4: Role in the Senate
Chapter 5: Complete List of Presidents Pro Tempore

President Pro Tempore

The Constitution provides for a president pro tempore to preside over the Senate in the absence of the vice president.

Except for the years from 1886 to 1947, the president pro tempore has been included in the list of succession if the offices of president and vice president become vacant.

In the Presidential Succession Act of 1792, the president pro tempore was next in line after the vice president.

In 1886 a new law removed the president pro tempore from the line of succession, substituting cabinet officers.

In 1947 a law changed the order of succession to place the Speaker of the House in line after the vice president, followed by the president pro tempore, and then the secretary of state and other cabinet officers in order of their departments' creation. This is the system in effect today.

Before 1890, the Senate elected a president pro tempore only for the period when the vice president would be absent. Since 1890, the president pro tempore holds office continuously until the election of another president pro tempore.

The president pro tempore designates other senators to preside in his absence, generally new members of the majority party. In the current 107th Congress, Senator Robert C. Byrd of West Virginia served as president pro tempore from January 3 to 20, 2001, and beginning again on June 6, 2001. Senator J. Strom Thurmond of South Carolina served from January 20 to June 6, 2001, at which time he became president pro tempore emeritus.

Constitutional Authority

The Constitution provides for two officers to preside over the Senate. The vice president of the United States is designated as the president of the Senate. In this capacity, the vice president was expected to preside at regular sessions of the Senate, casting votes only to break ties. From John Adams in 1789 to Alben Barkley in 1952, presiding over the Senate was the chief function of vice presidents, who had an office in the Capitol, received their staff support and office expenses through the legislative appropriations, and who often were not invited to participate in cabinet meetings or other executive activities. In 1953, Vice President Richard M. Nixon changed the vice presidency by moving his chief office from the Capitol to the White House, by directing his attention to executive functions, and by attending Senate sessions only at critical times when his vote, or ruling from the chair, might be necessary. Vice presidents since Nixon's time have followed his example.

When we consider that the vice president used to be the Senate's regular presiding officer, we can better understand why the Constitution further provided that in the absence of the vice president the Senate could choose a president pro tempore to perform the duties of the chair. Pro tempore is a Latin term meaning "for the time being"; thus, the occupant of the position was conceived as a temporary presiding officer. Since vice presidents presided routinely in the eighteenth and nineteenth centuries, the Senate thought it necessary to choose a president pro tempore only for the limited periods when the vice president might be ill or otherwise absent. As a result, the Senate frequently elected several presidents pro tempore during a single session.

The Constitution is quite unspecific in its definition of the vice president's role as presiding officer, beyond casting tie-breaking votes. John Adams, the first vice president, saw the presiding officer as a distinctly neutral figure, and what he began has remained constant over the past two centuries. Adams cast more tie-breaking votes (29) than has any vice president who succeeded him. By contrast, during his eight years of service in that post in the 1980's, George Bush cast only eight such votes. During his two terms as vice president, Albert Gore, Jr. cast four tie-breaking votes.

Perhaps the role as Adams viewed it is all we might reasonably have expected from vice presidents, but the situation of the president pro tempore is more ambiguous. Unlike the vice president, the president pro tempore is a duly elected member of the Senate, able to speak and vote on any issue. This official was therefore in a better position to assume leadership in the body, particularly in that era long before the creation of the posts of majority and minority leaders and party whips. (The vice president is not at liberty to address the Senate, except by unanimous consent. Nor should any senator speak while presiding, other than to make necessary rulings and announcements or to maintain order.)

Since the end of World War II, it has been traditional for the Senate to elect the senior member of the majority party as president pro tempore. In the earliest years, however, the Senate lacked both established parties and extended seniority. Presidents pro tempore, elected on a temporary basis, were chosen because of their personal characteristics, popularity, and reliability.

Presidential Succession

That the Senate took the post of president pro tempore seriously can be seen in the Presidential Succession Act of 1792. Should the offices of president and vice president both become vacant, the president pro tempore would succeed to the presidency, followed by the Speaker of the House. This succession remained in effect until 1886. The arrangement created a serious consequence on at least one occasion. When President Abraham Lincoln was assassinated in 1865, Vice President Andrew Johnson succeeded him, and the president pro tempore, Senator Lafayette S. Foster of Connecticut, became next in line to the White House. Senator Benjamin Wade of Ohio became president pro tempore in 1867. During Johnson's impeachment trial in 1868, had the Senate voted to remove him, Senator Wade would have become president of the United States. Senator Wade, it should be noted, cast his vote in favor of conviction, and President Johnson, after his acquittal, objected to placing the president pro tempore in the line of succession because he would therefore be "interested in producing a vacancy."

Vacancies in the office presented a most pressing problem. In the eighteenth and nineteenth centuries, the Senate assumed that it was empowered to elect a president pro tempore only during the absence of a vice president. But what should senators do at the end of a session? Since Congress was customarily out of session for half of each year, what would happen if there were no designated president pro tempore? If the vice president became president, who would preside at the opening of the next Senate session? Rather than settle these problems by statute or rules changes, the Senate for decades relied upon an elaborate charade in which the vice president would voluntarily absent himself from the chamber at the end of the session to enable the Senate to elect a president pro tempore, who would then be available to preside if necessary when the Senate reconvened. Some vice presidents refused to perform this little courtesy.

In 1886 Senator George F. Hoar of Massachusetts expressed concern about the frequency of vacancies in the vice presidency and office of president pro tempore and called for a revision of the succession act. "The present arrangement is bad," he told the Senate, because "during a large portion of the term there is no officer in being who can succeed." Senator Hoar argued that the Senate did not elect its presidents pro tempore based on any consideration of their fitness to become chief executive. The president pro tempore was by then a senior senator, chosen "for his capacity as a debater and a framer of legislation." Most likely, the president pro tempore would have "little or no executive experience." Hoar then pointed out that no president pro tempore had ever served as president, and only one had even been a candidate for president. By contrast, six secretaries of state had been elected president. Following Hoar's reasoning, Congress in 1886 passed a new law that removed the president pro tempore and Speaker of the House entirely from the line of presidential succession, leaving at its head the secretary of state and the other cabinet members, all non-elected officials.

This was the order of succession until 1947, when, at the urging of President Harry S. Truman, the law was again revised. Having served ten years in the Senate, Truman held the post of vice president only eighty-two days before Franklin Roosevelt's death propelled him into the White House. As a student of history and a fervent democrat, Truman was troubled that the next person in the line of succession was his secretary of state, Edward Stettinius. The secretary had never run for elective office, and as Truman stated, "it was my feeling that any man who stepped into the presidency should have held at least some office to which he had been elected by a vote of the people." Two months after becoming president, Truman proposed restoring the president pro tempore and Speaker of the House to the line of succession.

An interesting feature of Truman's proposal was its reversal of the earlier order of succession, putting the Speaker of the House ahead of the president pro tempore. There were several reasons for this change. In his memoirs, Truman argued that the House Speaker, as an elected representative of his district, as well as the chosen leader of the "elected representatives of the people," should stand next in line to the vice president. Of course, one could make the same argument for the president pro tempore, as the elected official of the people of his state and of the United States Senate. It is likely that specific personalities also played a role in Truman's thinking.

There may also have been an institutional factor in Truman's reversal of the roles. Between the 1886 removal of the president pro tempore from the order of succession and 1947, some entirely new leadership posts had evolved in the Senate: the majority and minority leaders and the party whips. Beginning in the 1920s, when the Democratic and Republican parties first officially designated floor leaders, a number of influential men had been elected majority leader. By 1945, most Washington observers regarded the majority leader as the Senate's functional equivalent of the Speaker of the House of Representatives, while the president pro tempore had become more of a ceremonial office. Had Truman drawn a list of men, rather than offices, he would certainly have included Majority Leader Alben Barkley in the line of succession -- indeed in 1948, Truman chose Senator Barkley as his vice presidential running mate. But, for the purposes of legislation, the president recommended inclusion of a constitutionally created officer, the president pro tempore, rather than a party-designated officer, the majority leader. Today the president pro tempore continues to follow the Speaker of the House in presidential succession, followed in turn by the secretary of state and the other cabinet secretaries in the order of their agencies' creation.

Role in the Senate

With regard to the president pro tempore's role in the Senate, an even more significant change took place in 1890, when the Senate agreed that, thereafter, presidents pro tempore would be elected not just for the period of the vice president's absence, but would hold the office continuously until the election of another president pro tempore. As a result, since 1890, with a single exception, each president pro tempore has served until he retired, died, or had the misfortune to see his party lose its majority.

The first sentence of Rule I of today's standing rules of the Senate provides that the president pro tempore shall hold the office "during the pleasure of the Senate and until another is elected or his term of office as a Senator expires." The so-called powers of the president pro tempore, which have generally been more responsibilities than powers, have changed a good deal over the past two centuries. Since 1816, presidents pro tempore have received a larger salary than other senators, and, for a period after 1856, they were compensated at the same rate as the vice president. Since March 1969, the salary of the president pro tempore has been the same as that of the majority and minority leaders. During the early nineteenth century, between 1823 and 1863, presidents pro tempore appointed members of the Senate's standing committees, either indirectly or directly. Since 1820, the president pro tempore has had the power to name other senators to perform the duties of the chair in his absence. In modern times, presidents pro tempore have tended to ask new members of the majority party to preside over the Senate, a practice which enables freshmen senators to grow more accustomed to the Senate's rules and procedures.

When the Democratic side is in the majority, the president pro tempore is an ex-officio member of his party's leadership, including the conference, the policy committee, and the steering committee, in which capacities he works closely with the majority leader. Under Republican majority, the president pro tempore is an ex-officio member of the Republican Policy Committee. Various laws assign the president pro tempore authority to make appointments to an assortment of national commissions, usually with the advice of the majority leader. If there are minority appointments, the president pro tempore generally acts upon the recommendations of the minority leader in appointing individuals acceptable to the minority. In the absence of the vice president, the president pro tempore may administer all oaths required by the Constitution, may sign legislation, and may fulfill all other obligations of the presiding officer. Also, in the absence of the vice president, the president pro tempore jointly presides with the Speaker of the House when the two houses sit together in joint sessions or joint meetings.

The president pro tempore works closely with the secretary and the sergeant at arms of the Senate, directing the enforcement of the rules governing the use of the Capitol and the Senate office buildings. Jointly with the Speaker of the House, and at the recommendation of the Budget committees, the president pro tempore appoints the director of the Congressional Budget Office. As an assistant to a former president pro tempore observed in 1981, the position has "the honor and with it the responsibility." The occupant of the office, he said, "makes more or less out of it."

Election of a senator to the office of president pro tempore has always been considered one of the highest honors offered to a senator by the Senate as a body. That honor has been bestowed upon a colorful and significant group of senators during the past two centuries -- men who stamped their imprint on the office and on their times.

Complete List of Presidents Pro Tempore

1st Congress (1789-1791)

John Langdon (NH)
April 6, 1789 - April 21, 1789
August 7, 1789 - August 9, 1789

2nd Congress (1791-1793)

Richard Henry Lee (VA)
April 18, 1792 - October 8, 1792

John Langdon (NH)
November 5, 1792 - December 4, 1792
March 1, 1793 - March 3, 1793

3rd Congress (1793-1795)

John Langdon (NH)
March 4, 1793 - December 2, 1793

Ralph Izard (SC)
May 31, 1794 - November 9, 1794

Henry Tazewell (VA)
February 20, 1795 - June 7, 1795

4th Congress (1795-1797)

Henry Tazewell (VA)
December 7, 1795 - December 8, 1795

Samuel Livermore (NH)
May 6, 1796 - December 4, 1796

William Bingham (PA)
February 16, 1797 - March 3, 1797

5th Congress (1797-1799)

William Bradford (RI)
July 6, 1797 - October 1797

Jacob Read (SC)
November 22, 1797 - December 12, 1797

Theodore Sedgwick (MA)
June 27, 1798 - December 5, 1798

John Laurance (NY)
December 6, 1798 - December 27, 1798

James Ross (PA)
March 1, 1799 - December 1, 1799

6th Congress (1799-1801)

Samuel Livermore (NH)
December 2, 1799 - December 29, 1799

Uriah Tracy (CT)
May 14, 1800 - November 16, 1800

John E. Howard (MD)
November 21, 1800 - November 27, 1800

James Hillhouse (CT)
February 28, 1801 - March 3, 1801

7th Congress (1801-1803)

Abraham Baldwin (GA)
December 7, 1801 - January 14, 1802
April 17, 1802 - December 13, 1802

Stephen R. Bradley (VT)
December 14, 1802 - January 18, 1803
February 25, 1803 - February 25, 1803
March 2, 1803 - October 16, 1803

8th Congress (1803-1805)

John Brown (KY)
October 17, 1803 - December 6, 1803
January 23, 1804 - February 26, 1804

Jesse Franklin (NC)
March 10, 1804 - November 4, 1804

Joseph Anderson (TN)
January 15, 1805 - February 3, 1805
February 28, 1805 - March 2, 1805
March 2, 1805 - December 1, 1805

9th Congress (1805-1807)

Samuel Smith (MD)
December 2, 1805 - December 15, 1805
March 18, 1806 - November 30, 1806
March 2, 1807 - October 25, 1807

10th Congress (1807-1809)

Samuel Smith (MD)
April 16, 1808 - November 6, 1808
Stephen R. Bradley (VT)
December 28, 1808 - January 8, 1809

John Milledge (GA)
January 30, 1809 - March 3, 1809

11th Congress (1809-1811)

John Milledge (GA)
March 4, 1809 - May 21, 1809

Andrew Gregg (PA)
June 26, 1809 - December 18, 1809

John Gaillard (SC)
February 28, 1810 - March 2, 1810
April 17, 1810 - December 11, 1810

John Pope (KY)
February 23, 1811 - November 3, 1811

12th Congress (1811-1813)

William Crawford (GA)
March 24, 1812 - March 23, 1813

13th Congress (1813-1815)

Joseph B. Varnum (MA)
December 6, 1813 - February 3, 1814

John Gaillard (SC)
April 18, 1814 - November 25, 1814
November 25, 1814 - December 3, 1815

Note: Gaillard was elected after the death of Vice President Elbridge Gerry and continued to serve throughout the Fourteenth Congress, as there was no vice president.

14th Congress (1815-1817

John Gaillard (SC)
December 4, 1815 - March 3, 1817

15th Congress (1817-1819)

John Gaillard (SC)
March 4, 1817 - March 4, 1817
March 6, 1817 - February 18, 1818
March 31, 1818 - January 5, 1819

James Barbour (VA)
February 15, 1819 - December 5, 1819

16th Congress (1819-1821)

James Barbour (VA)
December 6, 1819 - December 26, 1819

John Gaillard (SC)
January 25, 1820 - December 2, 1821

17th Congress (1821-1823)

John Gaillard (SC)
December 3, 1821 - December 27, 1821
February 1, 1822 - December 2, 1822
February 19, 1823 - November 30, 1823

18th Congress (1823-1825)

John Gaillard (SC)
December 1, 1823 - January 20, 1824
May 21, 1824 - March 3, 1825

19th Congress (1825-1827)

John Gaillard (SC)
March 9, 1825 - December 4, 1825

Nathaniel Macon (NC)
May 20, 1826 - December 3, 1826
January 2, 1827 - February 13, 1827
March 2, 1827 - December 2, 1827

20th Congress (1827-1829)

Samuel Smith (MD)
May 15, 1828 - December 18, 1828

21st Congress (1829-1831)

Samuel Smith (MD)
March 13, 1829 - December 10, 1829
May 29, 1830 - December 31, 1830
March 1, 1831 - December 4, 1831

22nd Congress (1831-1833)

Samuel Smith (MD)
December 5, 1831 - December 11, 1831

Littleton Tazewell (VA)
July 9, 1832 - July 16, 1832

Hugh L. White (TN)
December 3, 1832 - December 1, 1833

23rd Congress (1833-1835)

Hugh L. White (TN)
December 2, 1833 - December 15, 1833

George Poindexter (MS)
June 28, 1834 - November 30, 1834

John Tyler (VA)
March 3, 1835 - December 6, 1835

24th Congress (1835-1837)

William R. King (AL)
July 1, 1836 - December 4, 1836
January 28, 1837 - March 3, 1837

25th Congress (1837-1839)

William R. King (AL)
March 7, 1837 - September 3, 1837
October 13, 1837 - December 3, 1837
July 2, 1838 - December 18, 1838
February 25, 1839 - December 1, 1839

26th Congress (1839-1841)

William R. King (AL)
December 2, 1839 - December 26, 1839
July 3, 1840 - December 15, 1840
March 3, 1841 - March 3, 1841

27th Congress (1841-1843)

William R. King (AL)
March 4, 1841 - March 4, 1841

Samuel Southard (NJ)
March 11, 1841 - May 31, 1842

Willie P. Mangum (NC)
May 31, 1842 - December 3, 1843

28th Congress (1843-1845)

Willie P. Mangum (NC)
December 4, 1843 - March 3, 1845

29th Congress (1845-1847)

Willie P. Mangum (NC)
March 4, 1845 - March 4, 1845

Ambrose H. Sevier (AR)
December 27, 1845

David R. Atchison (MO)
August 8, 1846 - December 6, 1846
January 11, 1847 - January 13, 1847
March 3, 1847 - December 5, 1847

Note: Ambrose H. Sevier was not elected as president pro tempore in an official manner, but "permitted to occupy the chair for the day."

30th Congress (1847-1849)

David R. Atchison (MO)
February 2, 1848 - February 8, 1848
June 1, 1848 - June 14, 1848
June 26, 1848 - June 29, 1848
July 29, 1848 - December 4, 1848
December 26, 1848 - January 1, 1849
March 2, 1849 - March 4, 1849

31st Congress (1849-1851)

David R. Atchison (MO)
March 5, 1849 - March 5, 1849
March 16, 1849 - December 2, 1849

William R. King (AL)
May 6, 1850 - May 19, 1850
July 11, 1850 - March 3, 1851

32nd Congress (1851-1853)

William R. King (AL)
March 4, 1851 - December 20, 1852

David R. Atchison (MO)
December 20, 1852 - March 3, 1853

33rd Congress (1853-1855)

David R. Atchison (MO)
March 4, 1853 - December 4, 1854

Lewis Cass (MI)
December 4, 1854 - December 4, 1854

Jesse D. Bright (IN)
December 5, 1854 - December 2, 1855

34th Congress (1855-1857)

Jesse D. Bright (IN)
December 3, 1855 - June 9, 1856

Charles E. Stuart (MI)
June 9, 1856 - June 10, 1856

Jesse D. Bright (IN)
June 11, 1856 - January 6, 1857

James M. Mason (VA)
January 6, 1857 - March 3, 1857

35th Congress (1857-1859)

James M. Mason (VA)
March 4, 1857 - March 4, 1857

Thomas J. Rusk (TX)
March 14, 1857 - July 29, 1857

Benjamin Fitzpatrick (AL)
December 7, 1857 - December 20, 1857
March 29, 1858 - May 2, 1858
June 14, 1858 - December 5, 1858
January 19, 1859 - January 19, 1859
January 25, 1859 - February 9, 1859

36th Congress (1859-1861)

Benjamin Fitzpatrick (AL)
March 9, 1859 - December 4, 1859
December 19, 1859 - January 15, 1860
February 20, 1860 - February 26, 1860

Jesse D. Bright (IN)
June 12, 1860 - June 13, 1860

Benjamin Fitzpatrick (AL)
June 26, 1860 - December 2, 1860

Solomon Foot (VT)
February 16, 1861 - February 17, 1861

37th Congress (1861-1863)

Solomon Foot (VT)
March 23, 1861 - July 3, 1861
July 18, 1861 - December 1, 1861
January 15, 1862 - January 15, 1862
March 31, 1862 - May 21, 1862
June 19, 1862 - December 12, 1862
February 18, 1863 - March 3, 1863

38th Congress (1863-1865)

Solomon Foot (VT)
March 4, 1863 - December 6, 1863
December 18, 1863 - December 20, 1863
February 23, 1864 - February 23, 1864
March 11, 1864 - March 13, 1864
April 11, 1864 - April 13, 1864

Daniel Clark (NH)
April 26, 1864 - January 4, 1865
February 9, 1865 - February 19, 1865

39th Congress (1865-1867)

Lafayette S. Foster (CT)
May 7, 1865 - March 2, 1867

Benjamin F. Wade (OH)
March 2, 1867 - March 3, 1867

40th Congress (1867-1869)

Benjamin F. Wade (OH)
March 4, 1867 - March 3, 1869

41st Congress (1869-1871)

Henry B. Anthony (RI)
March 23, 1869 - March 28, 1869
April 9, 1869 - December 5, 1869
May 28, 1870 - June 2, 1870
July 1, 1870 - July 5, 1870
July 14, 1870 - December 4, 1870

42nd Congress (1871-1873)

Henry B. Anthony (RI)
March 10, 1871 - March 12, 1871
April 17, 1871 - May 9, 1871
May 23, 1871 - December 3, 1871
December 21, 1871 - January 7, 1872
February 23, 1872 - February 25, 1872
June 8, 1872 - December 1, 1872
December 4, 1872 - December 8, 1872
December 13, 1872 - December 15, 1872
December 20, 1872 - January 5, 1873
January 24, 1873 - January 24, 1873

43rd Congress (1873-1875)

Matthew H. Carpenter (WI)
March 12, 1873 - March 13, 1873
March 26, 1873 - November 30, 1873
December 11, 1873 - December 6, 1874
December 23, 1874 - January 4, 1875

Henry B. Anthony (RI)
January 25, 1875 - January 31, 1875
February 15, 1875 - February 17, 1875

44th Congress (1875-1877)

Thomas W. Ferry (MI)
March 9, 1875 - March 10, 1875
March 19, 1875 - December 20, 1875
December 20, 1875 - March 4, 1877

45th Congress (1877-1879)

Thomas W. Ferry (MI)
March 5, 1877 - March 5, 1877
February 26, 1878 - March 3, 1878
April 17, 1878 - December 1, 1878
March 3, 1879 - March 17, 1879

46th Congress (1879-1881)

Allen G. Thurman (OH)
April 15, 1879 - November 30, 1879
April 7, 1880 - April 14, 1880
May 6, 1880 - December 5, 1880

47th Congress (1881-1883)

Thomas F. Bayard (DE)
October 10, 1881 - October 13, 1881

David Davis (IL)
October 13, 1881 - March 3, 1883

George F. Edmunds (VT)
March 3, 1883 - December 2, 1883

48th Congress (1883-1885)

George F. Edmunds (VT)
December 3, 1883 - January 14, 1884
January 14, 1884 - March 3, 1885

49th Congress (1885-1887)

John Sherman (OH)
December 7, 1885 - February 26, 1887

John J. Ingalls (KS)
February 26, 1887 - December 4, 1887

50th Congress (1887-1889)

John J. Ingalls (KS)
December 5, 1887 - March 3, 1889

51st Congress (1889-1891)

John J. Ingalls (KS)
March 7, 1889 - March 17, 1889
April 2, 1889 - December 1, 1889
December 5, 1889 - December 10, 1889
February 28, 1890 - March 18, 1890
April 3, 1890 - March 2, 1891

Charles F. Manderson (NE)
March 2, 1891 - December 6, 1891

Note: In March, 1890, the Senate adopted a resolution stating that presidents pro tempore would hold office continuously until the election of another president pro tempore, rather than being elected for the period in which the vice president was absent. With the exception of the unusual case of the 62nd Congress, this new system has continued to the present.

52nd Congress (1891-1893)

Charles F. Manderson (NE)
December 7, 1891 - March 3, 1893

53rd Congress (1893-1895)

Charles F. Manderson (NE)
March 4, 1893 - March 22, 1893

Isham G. Harris (TN)
March 22, 1893 - January 7, 1895

Matt W. Ransom (NC)
January 7, 1895 - January 10, 1895

Isham G. Harris (TN)
January 10, 1895 - March 3, 1895

54th Congress (1895-1897)

William P. Frye (ME)
February 7, 1896 - March 3, 1897

55th Congress (1897-1899)

William P. Frye (ME)
March 4, 1897 - December 3, 1899

56th Congress (1899-1901)

William P. Frye (ME)
December 4, 1899 - March 3, 1901

57th Congress (1901-1903)

William P. Frye (ME)
March 7, 1901 - March 4, 1903

58th Congress (1903-1905)

William P. Frye (ME)
March 5, 1903 - March 3, 1905

59th Congress (1905-1907)

William P. Frye (ME)
March 4, 1905 - March 3, 1907

60th Congress (1907-1909)

William P. Frye (ME)
December 5, 1907 - March 3, 1909

61st Congress (1909-1911)

William P. Frye (ME)
March 4, 1909 - April 3, 1911

62nd Congress (1911-1913)

William P. Frye (ME)
April 4, 1911 - April 27, 1911

Augustus O. Bacon (GA)
August 14, 1911 - August 14, 1911

Charles Curtis (KS)
December 4, 1911 - December 12, 1911

Augustus O. Bacon (GA)
January 15, 1912 - January 17, 1912

Jacob H. Gallinger (NH)
February 12, 1912 - February 14, 1912

Augustus O. Bacon (GA)
March 11, 1912 - March 12, 1912

Frank B. Brandegee (CT)
March 25, 1912 - March 26, 1912

Augustus O. Bacon (GA)
April 8, 1912 - April 8, 1912

Jacob H. Gallinger (NH)
April 26, 1912 - April 27, 1912
May 7, 1912 - May 7, 1912

Augustus O. Bacon (GA)
May 10, 1912 - May 10, 1912

Henry Cabot Lodge (MA)
May 25, 1912 - May 25, 1912

Augustus O. Bacon (GA)
May 30, 1912 - June 3, 1912
June 13, 1912 - July 5, 1912

Jacob H. Gallinger (NH)
July 6, 1912 - July 31, 1912

Augustus O. Bacon (GA)
August 1, 1912 - August 10, 1912

Jacob H. Gallinger (NH)
August 12, 1912 - August 26, 1912

Augustus O. Bacon (GA)
August 27, 1912 - December 15, 1912

Jacob H. Gallinger (NH)
December 16, 1912 - January 4, 1913

Augustus O. Bacon (GA)
January 5, 1913 - January 18, 1913

Jacob H. Gallinger (NH)
January 19, 1913 - February 1, 1913

Augustus O. Bacon (GA)
February 2, 1913 - February 15, 1913

Jacob H. Gallinger (NH)
February 16, 1913 - March 3, 1913

Note: William Frye resigned as president pro tempore due to ill health and died on August 8, 1911. Electing his successor proved difficult for the Senate, since Senate Republicans, then in the majority, split between the progressive and the conservative factions, each promoting its own candidate. Likewise, the Democrats proposed their own candidate. As a result of this three-way split, no individual received a majority vote. During May and June of 1911, ballot after ballot failed to elect a president pro tempore. Finally, desperate to return to regular business, senators agreed to a compromised solution: Democrat Augustus Bacon would serve for a single day, August 14, 1911, during the vice president's absence. Thereafter, Bacon and four Republicans -- Charles Curtis, Jacob Gallinger, Henry Cabot Lodge, and Frank Brandegee -- would alternate as president pro tempore for the remainder of the 62nd Congress.

63rd Congress (1913-1915)

James P. Clarke (AR)
March 13, 1913 - March 3, 1915

64th Congress (1915-1917)

James P. Clarke (AR)
December 6, 1915 - October 1, 1916

Willard Saulsbury (DE)
December 14, 1916 - March 4, 1917

65th Congress (1917-1919)

Willard Saulsbury (DE)
March 5, 1917 - March 3, 1919

66th Congress (1919-1921)

Albert B. Cummins (IA)
May 19, 1919 - March 3, 1921

67th Congress (1921-1923)

Albert B. Cummins (IA)
March 7, 1921 - December 2, 1923

68th Congress (1923-1925)

Albert B. Cummins (IA)
December 3, 1923 - March 3, 1925

69th Congress (1925-1927)

Albert B. Cummins (IA)
March 4, 1925 - March 6, 1925

George H. Moses (NH)
March 6, 1925 - March 4, 1927

70th Congress (1927-1929)

George H. Moses (NH)
December 15, 1927 - March 3, 1929

71st Congress (1929-1931)

George H. Moses (NH)
March 4, 1929 - December 6, 1931

72nd Congress (1931-1933)

George H. Moses (NH)
December 7, 1931 - March 3, 1933

73rd Congress (1933-1935)

Key Pittman (NV)
March 9, 1933 - January 2, 1935

74th Congress (1935-1937)

Key Pittman (NV)
January 7, 1935 - January 4, 1937

75th Congress (1937-1939)

Key Pittman (NV)
January 5, 1937 - January 2, 1939

76th Congress (1939-1941)

Key Pittman (NV)
January 3, 1939 - November 10, 1940

William H. King (UT)
November 19, 1940 - January 3, 1941

77th Congress (1941-1943)

Pat Harrison (MS)
January 6, 1941 - June 22, 1941

Carter Glass (VA)
July 10, 1941 - January 5, 1943

78th Congress (1943-1945)

Carter Glass (VA)
January 14, 1943 - January 2, 1945

79th Congress (1945-1947)

Kenneth McKellar (TN)
January 6, 1945 - January 2, 1947

80th Congress (1947-1949)

Arthur H. Vandenberg (MI)
January 4, 1947 - January 2, 1949

81st Congress (1949-1951)

Kenneth McKellar (TN)
January 3, 1949 - January 2, 1951

82nd Congress (1951-1953)

Kenneth McKellar (TN)
January 3, 1951 - January 2, 1953

83rd Congress (1953-1955)

Styles Bridges (NH)
January 3, 1953 - January 4, 1955

84th Congress (1955-1957)

Walter F. George (GA)
January 5, 1955 - January 2, 1957

85th Congress (1957-1959)

Carl T. Hayden (AZ)
January 3, 1957 - January 6, 1959

86th Congress (1959-1961)

Carl T. Hayden (AZ)
January 7, 1959 - January 2, 1961

87th Congress (1961-1963)

Carl T. Hayden (AZ)
January 3, 1961 - January 8, 1963

88th Congress (1963-1965)

Carl T. Hayden (AZ)
January 9, 1963 - January 3, 1965

89th Congress (1965-1967)

Carl T. Hayden (AZ)
January 4, 1965 - January 9, 1967

90th Congress (1967-1969)

Carl T. Hayden (AZ)
January 10, 1967 - January 2, 1969

91st Congress (1969-1971)

Richard B. Russell (GA)
January 3, 1969 - January 20, 1971

92nd Congress (1971-1973)

Richard B. Russell (GA)
January 21, 1971 - January 21, 1971

Allen J. Ellender (LA)
January 22, 1971 - July 27, 1972

James O. Eastland (MS)
July 28, 1972 - January 2, 1973

93rd Congress (1973-1975)

James O. Eastland (MS)
January 3, 1973 - January 13, 1975

94th Congress (1975-1977)

James O. Eastland (MS)
January 14, 1975 - January 3, 1977

95th Congress (1977-1979)

James O. Eastland (MS)
January 4, 1977 - December 27, 1978

96th Congress (1979-1981)

Warren G. Magnuson (WA)
January 15, 1979 - December 4, 1980

Milton R. Young (ND)
December 5, 1980 - December 5, 1980

Warren G. Magnuson (WA)
December 6, 1980 - January 4, 1981

97th Congress (1981-1983)

Strom Thurmond (SC)
January 5, 1981 - January 2, 1983

98th Congress (1983-1985)

Strom Thurmond (SC)
January 3, 1983 - January 2, 1985

99th Congress (1985-1987)

Strom Thurmond (SC)
January 3, 1985 - January 5, 1987

100th Congress (1987-1989)

John C. Stennis (MS)
January 6, 1987 - January 2, 1989

101st Congress (1989-1991)

Robert C. Byrd (WV)
January 3, 1989 - January 2, 1991

102nd Congress (1991-1993)

Robert C. Byrd (WV)
January 3, 1991 - January 4, 1993

103rd Congress (1993-1995)

Robert C. Byrd (WV)
January 5, 1993 - January 3, 1995

104th Congress (1995-1997)

Strom Thurmond (SC)
January 4, 1995 - January 6, 1997

105th Congress (1997-1999)

Strom Thurmond (SC)
January 7, 1997 - January 6, 1999

106th Congress (1999-2001)

Strom Thurmond (SC)
January 7, 1999-January 3, 2001

107th Congress (2001-2003)

Robert C. Byrd (WV)
January 3, 2001 - January 20, 2001

Strom Thurmond (SC)
January 20, 2001-June 6, 2001

Robert C. Byrd (WV)
June 6, 2001 - January 3, 2003

Note:From January 3 to January 20, 2001 the Democrats held the majority, due to the deciding vote of outgoing Democratic Vice President Al Gore. Senator Robert C. Byrd became president pro tempore at that time. Starting January 20, 2001, the incoming Republican Vice President Richard Cheney held the deciding vote, giving the majority to the Republicans. Senator Strom Thurmond resumed his role as president pro tempore. On May 24, 2001, Senator James Jeffords of Vermont announced his switch from Republican to Independent status, effective June 6, 2001. Jeffords announced that he would caucus with the Democrats, changing control of the evenly divided Senate from the Republicans to the Democrats. On June 6, 2001, Robert C. Byrd once again became president pro tempore. On that day, the Senate adopted S. Res. 103, designating Senator Thurmond as President Pro Tempore Emeritus.

108th Congress (2003-2005)

Theodore (Ted) Stevens (AK)
Tenure: January 3, 2003 -- January 4, 2005

109th Congress (2005-2007)

Theodore (Ted) Stevens (AK)
Tenure: January 4, 2005 -- January 4, 2007

110th Congress (2007-2009)

Robert C. Byrd (West Virginia)
Tenure: January 4, 2007 -- present

Source: http://www.senate.gov/artandhistory/history/common/briefing/President_Pro_Tempore.htm#5