Special Elections

Article I of the Constitution provides that when a House seat becomes vacant, the governor of the state shall issue writs of election to fill it, so House vacancies can be filled only by election, never by appointment. The Seventeenth Amendment, ratified in 1913, requires special elections for Senate vacancies as well but allows state legislatures to let governors make temporary appointments until the election, which most states do. States set the timing and procedures, so the gap between a vacancy and a special election ranges from a few months to nearly a year.

Special elections often have low turnout and draw intense national attention and spending, especially when they come between regular elections and the parties are closely divided. Notable examples include the 2010 Massachusetts Senate special election, which cost Democrats their 60th Senate vote during the health care debate, and the 2017 Alabama Senate special election won by a Democrat in a strongly Republican state. Because results can diverge from normal patterns, analysts treat swings in special elections as rough indicators of the national political climate.

Special elections matter more when House margins are narrow, since each vacancy changes the number of votes the majority can lose. In 2025 several House seats became vacant after resignations to join the administration and deaths of members, and their special elections were watched closely for their effect on the majority and as signals ahead of the 2026 midterms. Some reformers have proposed requiring faster special elections or allowing temporary appointments to the House in emergencies, while others say only voters should fill House seats.