List of United States senators who switched parties
{{Short description|None}}
{{Use mdy dates|date=April 2025}}
This list includes United States senators who switched parties while serving in the Senate.
List
=19th century=
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! Senator ! State ! Date ! Congress ! Old party ! New party ! Notes |
| nowrap| James H. Kyle
| 1891 | rowspan=1 | 52nd | {{party shading/Independent (United States)}} | Independent | {{party shading/Populist}} | Populist | |
| nowrap| William Morris Stewart
| Nevada | 1893 | rowspan=2 | 53rd | {{party shading/Republican}} | Republican | style="background:#F2CED4" | Silver |rowspan=9| The Silver Republicans' seniority and committee assignments were not affected by their having left the party.{{cite web |url=https://www.senate.gov/artandhistory/history/common/briefing/senators_changed_parties.htm |title=Senators Who Changed Parties During Senate Service (Since 1890) |publisher=United States Senate}} |
| John P. Jones
| Nevada | September 4, 1894 | {{party shading/Republican}} | Republican | style="background:#F2CED4" | Silver |
| Henry M. Teller
| Colorado | rowspan= 4 | June 17, 1896 | rowspan=5 | 54th | {{party shading/Republican}} | Republican | style="background:#F2CED4" | Silver |
| Lee Mantle
| Montana | {{party shading/Republican}} | Republican | style="background:#F2CED4" | Silver |
| nowrap| Richard F. Pettigrew
| {{party shading/Republican}} | Republican | style="background:#F2CED4" | Silver |
| nowrap| Frank J. Cannon
| Utah | {{party shading/Republican}} | Republican | style="background:#F2CED4" | Silver |
| Fred Dubois
| Idaho | 1896 | {{party shading/Republican}} | Republican | style="background:#F2CED4" | Silver |
| James H. Kyle
| 1897 | 55th | {{party shading/Populist}} | Populist | {{party shading/Republican}} | Republican |
| William Morris Stewart
| Nevada | December 4, 1899 | 56th | style="background:#F2CED4" | Silver | {{party shading/Republican}} | Republican |
=20th century=
| class=wikitable |
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! Senator ! State ! Date ! Congress ! Old party ! New party ! Notes |
| John P. Jones
| Nevada | rowspan=2 | 1901 | rowspan=3| 56th | style="background:#F2CED4" | Silver | {{party shading/Republican}} | Republican |
| Fred Dubois
| Idaho | style="background:#F2CED4" | Silver | {{party shading/Democratic}} | Democratic | DuBois lost his re-election bid in 1896, was again elected as a Silver Republican in 1900, but became a Democrat early in the term. |
| Henry M. Teller
| Colorado | March 4, 1901 | style="background:#F2CED4" | Silver | {{party shading/Democratic}} | Democratic |
| rowspan=2 nowrap | Miles Poindexter
| rowspan=2 | Washington | 1913 | 63rd | {{party shading/Republican}} | Republican | {{party shading/Progressive}} | Progressive |
| 1915
| 64th | {{party shading/Progressive}} | Progressive | {{party shading/Republican}} | Republican |
| nowrap| Robert M. La Follette Jr.
| 1935 | 74th | {{party shading/Republican}} | Republican | {{party shading/Progressive (Wisconsin)}} | Progressive | Caucused with the Republicans; briefly returned before losing in 1946. |
| nowrap| George W. Norris
| Nebraska | 1937 | 75th | {{party shading/Republican}} | Republican | {{party shading/Independent (United States)}} | Independent |
| nowrap| Henrik Shipstead
| 1940 | 76th | {{party shading/Farmer-Labor}} | Farmer–Labor | {{party shading/Republican}} | Republican |
| rowspan=2 nowrap| Wayne Morse
| rowspan=2| Oregon | 1953 | 83rd | {{party shading/Republican}} | Republican | {{party shading/Independent (United States)}} | Independent |
| February 17, 1955
| 84th | {{party shading/Independent (United States)}} | Independent | {{party shading/Democratic}} | Democratic | |
| nowrap| Strom Thurmond
|nowrap| September 16, 1964 | 88th | {{party shading/Democratic}} | Democratic | {{party shading/Republican}} | Republican |
| nowrap| Harry F. Byrd Jr.
| Virginia | 1970 | 91st | {{party shading/Democratic}} | Democratic | {{party shading/Independent (United States)}} | Independent | Kept seniority, but did not caucus with the Democrats |
| nowrap| James L. Buckley
| New York | 1976 | 94th | {{party shading/Conservative (New York)}} | Conservative | {{party shading/Republican}} | Republican | |
| nowrap| Richard Shelby
| Alabama | November 9, 1994 | 103rd | {{party shading/Democratic}} | Democratic | {{party shading/Republican}} | Republican |
| nowrap| Ben Nighthorse Campbell
| Colorado | March 3, 1995 | 104th | {{party shading/Democratic}} | Democratic | {{party shading/Republican}} | Republican |
| rowspan=4 nowrap| Robert Smith
|rowspan=4| New Hampshire |
| July 13, 1999
| rowspan=4| 106th | {{party shading/Republican}} | Republican | {{party shading/Constitution}} | Taxpayers |
| August 1999
| {{party shading/Constitution}} | Taxpayers | {{party shading/Independent (United States)}} | Independent |
| November 1, 1999
| {{party shading/Independent (United States)}} | Independent | {{party shading/Republican}} | Republican |
=21st century=
| class=wikitable |
| valign=bottom
! Senator ! State ! Date ! Congress ! Old party ! New party ! Notes |
| nowrap| Jim Jeffords
| Vermont | June 6, 2001 | 107th | {{party shading/Republican}} | Republican | {{party shading/Independent (United States)}} | Independent | Caucused with the Democrats. Gave Democrats temporary control of the senate. |
| nowrap| Joe Lieberman
| 2006 | 110th | {{party shading/Democratic}} | Democratic | {{party shading/Independent Democratic}} | Independent | Caucused with the Democrats. Lieberman was re-elected on the Connecticut for Lieberman ticket; however, he never formally joined that political party. |
| nowrap| Arlen Specter{{cite news |title=Longtime GOP Sen. Arlen Specter becomes Democrat |url=http://www.cnn.com/2009/POLITICS/04/28/specter.party.switch/index.html |date=April 28, 2009 |work=CNN |access-date=April 28, 2009 }}
| April 28, 2009 | 111th | {{party shading/Republican}} | Republican | {{party shading/Democratic}} | Democratic | Originally a Democrat |
| nowrap| Kyrsten Sinema{{cite news |title=Sinema leaving the Democratic Party and registering as an independent |url=https://www.cnn.com/2022/12/09/politics/kyrsten-sinema-leaves-democratic-party/index.html |date=December 9, 2022 |work=CNN |access-date=December 9, 2022 }}
| Arizona | December 9, 2022 | 117th | {{party shading/Democratic}} | Democratic | {{party shading/Independent (United States)}} | Independent | Caucused with the Democrats |
| nowrap| Joe Manchin{{Cite web |last=Irwin |first=Lauren |date=2024-05-31 |title=Joe Manchin leaves Democratic Party, files as independent |url=https://thehill.com/homenews/senate/4696125-manchin-independent-leaves-democrats/ |access-date=2024-05-31 |website=The Hill |language=en-US}}
| May 31, 2024 | 118th | {{party shading/Democratic}} | Democratic | {{party shading/Independent (United States)}} | Independent | Caucused with the Democrats |