# List of United States senators who switched parties

Complete since 1890 This list includes United States senators who switched parties while serving in the Senate.

## List
### 19th century

| Senator | State | Date | Congress | Old party | New party | Notes |
| James H. Kyle | South Dakota | 1891 | 52nd | Independent | Populist | |
| William Morris Stewart | Nevada | 1893 | 53rd | Republican | Silver Republican | The Silver Republicans' seniority and committee assignments were not affected by their having left the party. |
| John P. Jones | Nevada | September 4, 1894 | 53rd | Republican | Silver Republican | The Silver Republicans' seniority and committee assignments were not affected by their having left the party. |
| Henry M. Teller | Colorado | June 17, 1896 | 54th | Republican | Silver Republican | The Silver Republicans' seniority and committee assignments were not affected by their having left the party. |
| Lee Mantle | Montana | June 17, 1896 | 54th | Republican | Silver Republican | The Silver Republicans' seniority and committee assignments were not affected by their having left the party. |
| Richard F. Pettigrew | South Dakota | June 17, 1896 | 54th | Republican | Silver Republican | The Silver Republicans' seniority and committee assignments were not affected by their having left the party. |
| Frank J. Cannon | Utah | June 17, 1896 | 54th | Republican | Silver Republican | The Silver Republicans' seniority and committee assignments were not affected by their having left the party. |
| Fred Dubois | Idaho | 1896 | 54th | Republican | Silver Republican | The Silver Republicans' seniority and committee assignments were not affected by their having left the party. |
| James H. Kyle | South Dakota | 1897 | 55th | Populist | Republican | The Silver Republicans' seniority and committee assignments were not affected by their having left the party. |
| William Morris Stewart | Nevada | December 4, 1899 | 56th | Silver Republican | Republican | The Silver Republicans' seniority and committee assignments were not affected by their having left the party. |

### 20th century

| Senator | State | Date | Congress | Old party | New party | Notes |
| John P. Jones | Nevada | 1901 | 56th | Silver Republican | Republican |
| Fred Dubois | Idaho | 1901 | 56th | Silver Republican | 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 | 56th | Silver Republican | Democratic |
| Miles Poindexter | Washington | 1913 | 63rd | Republican | Progressive |
| Miles Poindexter | Washington | 1915 | 64th | Progressive | Republican |
| Robert M. La Follette Jr. | Wisconsin | 1935 | 74th | Republican | Progressive | Caucused with the Republicans; briefly returned before losing in 1946. |
| George W. Norris | Nebraska | 1937 | 75th | Republican | Independent |
| Henrik Shipstead | Minnesota | 1940 | 76th | Farmer–Labor | Republican |
| Wayne Morse | Oregon | 1953 | 83rd | Republican | Independent |
| Wayne Morse | Oregon | February 17, 1955 | 84th | Independent | Democratic | |
| Strom Thurmond | South Carolina | September 16, 1964 | 88th | Democratic | Republican |
| Harry F. Byrd Jr. | Virginia | 1970 | 91st | Democratic | Independent | Kept seniority, but did not caucus with the Democrats |
| James L. Buckley | New York | 1976 | 94th | Conservative | Republican | |
| Richard Shelby | Alabama | November 9, 1994 | 103rd | Democratic | Republican |
| Ben Nighthorse Campbell | Colorado | March 3, 1995 | 104th | Democratic | Republican |
| Robert Smith | New Hampshire |
| Robert Smith | New Hampshire | July 13, 1999 | 106th | Republican | Taxpayers |
| Robert Smith | New Hampshire | August 1999 | 106th | Taxpayers | Independent |
| Robert Smith | New Hampshire | November 1, 1999 | 106th | Independent | Republican |

### 21st century

| Senator | State | Date | Congress | Old party | New party | Notes |
| Jim Jeffords | Vermont | June 6, 2001 | 107th | Republican | Independent | Caucused with the Democrats. Gave Democrats temporary control of the senate. |
| Joe Lieberman | Connecticut | 2006 | 110th | Democratic | Independent Democrat | Caucused with the Democrats. Lieberman was re-elected on the Connecticut for Lieberman ticket; however, he never formally joined that political party. |
| Arlen Specter | Pennsylvania | April 28, 2009 | 111th | Republican | Democratic | Originally a Democrat |
| Kyrsten Sinema | Arizona | December 9, 2022 | 117th | Democratic | Independent | Caucused with the Democrats |
| Joe Manchin | West Virginia | May 31, 2024 | 118th | Democratic | Independent | Caucused with the Democrats |