Prior to ratification of the
Seventeenth Amendment to the United States Constitution in 1913, most state legislatures elected senators, as well as replacement senators. Some states empowered their governor to make temporary appointments until the legislature was in session. The Seventeenth Amendment now requires the
governor of the state to issue a writ for a special election to fill a vacant Senate seat, but no timeframe is specified in the provision for when the special election is to be held. State legislatures may also empower the governor to fill a vacancy by a temporary appointment until the winner of the special election is certified. The constitution does not state how the temporary appointee is to be selected, or that there is no federal requirement that the appointee be of the same party, as it happened in
New Jersey in 2013, and the state legislature can legislate as to how the replacement is to be selected.
Kentucky,
North Dakota,
Wisconsin and
Rhode Island do not empower the governor to make temporary appointments and require special elections. Between 2004 and 2008,
Massachusetts denied the power of the governor to appoint a replacement; in 2004, the
Democratic-controlled legislature wanted to limit the power of
Republican governor Mitt Romney to appoint a successor to then-
senator John Kerry if he were elected president that year. After the death of senator
Ted Kennedy, the legislature chose to revert the rules to allow Democratic governor
Deval Patrick to appoint a temporary replacement senator while awaiting the results of a special election to complete the existing term.
Hawaii allows the governor to appoint an interim senator "who serves until the next regularly-scheduled general election, chosen from a list of three prospective appointees that the prior incumbent's political party submits".
Alaska enacted conflicting legislation and a separate ballot
referendum law in 2004, which went into effect immediately. It is uncertain if the Alaska governor may successfully appoint an interim senator to serve until the mandated special election occurs 60 to 90 days after the vacancy happens. The ballot-approved law fails to specifically authorize the governor to appoint, though the legislative law does. Kentucky did away with the governor's appointment entirely in 2024, over Governor
Andy Beshear's veto, and legislated only special elections to fill further Senate vacancies. In 2025,
Oregon reinstated the gubernatorial power to appoint a successor also of the same party as the senator who vacates the seat, but disallows the governor to appoint oneself to the Senate. However, a special election must be called within several weeks or a few months of the vacancy. ==List of special elections==