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Filling vacancies in the U.S. Senate
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This article details how vacancies are filled when they occur in the U.S. Senate.
In 35 states, vacancies are temporarily filled by gubernatorial appointment. A special election is then held, coinciding with the next regularly scheduled election, to replace the appointee. In the remaining 15 states, a special election is required within a certain time frame to fill the vacancy. Of those 15 states, 11 allow for an interim gubernatorial appointment.
For information on how vacancies are filled in the U.S. House of Representatives, click here.
Background
Article I, section 3 of the U.S. Constitution originally gave state legislatures the power to appoint a replacement in the U.S. Senate if the legislature was in session at the time of the vacancy. If the legislature was not in session, the state's governor would appoint a replacement to serve until the legislature could fill the vacancy.[1] However, the U.S. Congress passed the Seventeenth Amendment on May 13, 1912, which allows legislatures to authorize governors to appoint a replacement until a special election. It was ratified on April 8, 1913.
Gubernatorial appointment
In 35 states, U.S. Senate vacancies are temporarily filled by gubernatorial appointment. A special election is then held, coinciding with the next regularly scheduled election, to replace the appointee. The winner in that general election serves out the remainder of the term.[2]
- Arkansas[3]
- Arizona[4]
- California
- Colorado
- Delaware
- Florida
- Georgia
- Hawaii[4][5][6]
- Idaho
- Illinois
- Indiana
- Iowa
- Kansas[4]
- Maine
- Maryland[4]
- Michigan
- Minnesota[5]
- Missouri
- Montana[4]
- Nebraska
- Nevada[4]
- New Hampshire
- New Jersey[5]
- New Mexico
- New York[5]
- North Carolina[4]
- Ohio
- Pennsylvania
- South Carolina
- South Dakota
- Tennessee
- Utah[4]
- Virginia[5]
- West Virginia[4]
- Wyoming[4]
Special election
In 11 states, U.S. Senate vacancies are temporarily filled by gubernatorial appointment. A special election is then held within a certain time frame to fill the vacancy. In four other states, U.S. Senate vacancies are filled solely by a special election.[2]
| State | Interim gubernatorial appointment? | When must the special election be held? |
|---|---|---|
| Alabama | Yes | A special election must be held "forthwith" if the vacancy occurs more than four months before the next general election. |
| Alaska | Yes | 60-90 days after the vacancy occurs. |
| Connecticut | Yes | The 160th day after the vacancy occurs (excluding weekends), unless the vacancy occurs between the 125th and 63rd days prior to a regularly-scheduled November general election. In this case, the vacancy is filled at that election. |
| Kentucky | No | At least 56 days before the election, the governor issues a proclamation and directs it to the sheriffs in each county in which an election is to be held. Those sheriffs must then give notice of the election at least 49 days before the election. |
| Louisiana | Yes | No less than 11 weeks after the governor's proclamation of the special election. |
| Massachusetts | Yes | 145-160 days after the vacancy occurs. |
| Mississippi | Yes | Within 100 days of the governor's receipt of an official notice of vacancy; if the vacancy occurs in the year of a general state or congressional election, the vacancy must be filled in that election. |
| North Dakota | No | Within 95 days of the vacancy, unless the vacancy occurs within 95 days of the office term-end date.[7] |
| Oklahoma | Yes | The special election must be announced within 30 days after the vacancy occurs. Within 10 days of this announcement, a three-day filing period must occur. Within 20 days of the close of the candidate filing period, a special primary must take place. A primary runoff, if required, must take place within 20 days of the special primary. The special general election must take place within 20 days of the special primary runoff. If the vacancy occurs during an even-numbered year, it must be filled at the regular primary and general elections. |
| Oregon | Yes | The special election must be announced no fewer than 80 days and no more than 150 days after the vacancy occurs. |
| Rhode Island | No | Not specified; if the vacancy occurs between July 1 and October 1 in an even-numbered year, the special election to fill the vacancy must take place concurrently with the regularly-scheduled general election. |
| Texas | Yes | If the vacancy occurs in an even-numbered year on or before the 62nd day preceding the primary, the vacancy must be filled at the next general election. If the vacancy occurs after this point or in an odd-numbered year, a special election must be held on or after the 36th day the election is ordered. |
| Vermont | Yes | Six months following the vacancy; if the vacancy occurs within 6 months of a regularly scheduled general election, the vacancy may be filled at a special election coinciding with the general election.[8] |
| Washington | Yes | No fewer than 80 days after the vacancy occurs, unless the vacancy occurs within 8 months of a regularly scheduled general election, in which case the vacancy must be filled at the general election. |
| Wisconsin | No | Between 62 and 77 days after the special election is ordered, unless the vacancy occurs between the second Tuesday in May and the second Tuesday in July in an even-numbered year; in that case, the vacancy must be filled at the regular primary and general elections. |
Historical context
Between 1987 and 2024, there were at least 33 special elections in the U.S. Senate and 172 in the U.S. House. Ballotpedia compiled, where available, data for these special elections, including the party of the winner, the margin of victory, the number of votes cast, the reason for the special election, and the partisan control of the chamber and White House at the time of the election. The same data was collected for comparative purposes for the preceding and subsequent elections in that district or state.
- In 39 percent of the U.S. Senate special elections during this time period, the seat flipped. Of those flipped seats, 21 percent remained flipped in the subsequent regular cycle election.
- In 16 percent of the U.S. House special elections during this time period, the seat flipped. Of those flipped seats, 75 percent remained flipped in the subsequent regular cycle election.
For more information on the special elections to fill vacancies in the U.S. Senate, click here.
Footnotes
- ↑ Senate.gov, "About Electing and Appointing Senators | Filling Vacancies," accessed February 13, 2025
- ↑ 2.0 2.1 National Conference of State Legislatures, "Vacancies in the United States Senate," accessed July 11, 2025
- ↑ Note: If the vacancy occurs less than four months before the next scheduled general election, the appointed member serves until the second general election post-dating the vacancy.
- ↑ 4.0 4.1 4.2 4.3 4.4 4.5 4.6 4.7 4.8 4.9 Note: The appointed person must belong to the same political party as the senator who vacated the seat.
- ↑ 5.0 5.1 5.2 5.3 5.4 Note: If the vacancy occurs before a specific number of days prior to the regular primary (Hawaii: 21 days; Minnesota: 11 weeks; New Jersey: 30 days; New York: 59 days; Virginia: 120 days), the election is held the following November. If the vacancy occurs within the period of days before the regular primary, the election is held at the second November election after the vacancy occurs.
- ↑ Note: The governor makes the appointment by selecting from a list of three candidates provided by the party of the previous senator.
- ↑ North Dakota Century Code, "Section 16.1-13-08: General Elections, Filling vacancy in office of United States senator," accessed December 10, 2019
- ↑ Vermont Statutes, "Section 17-53-2621," accessed January 14, 2020
