National elections take place every even-numbered year. Every four years the president, vice president, one third of the Senate, and the entire House are up for election (on-year elections). On even-numbered years when there isn't a presidential election, one third of the Senate and the whole House are included in the election (off-year elections).
The Guidebook compiles federal and state laws relating to the nomination and election of candidates to the Senate.
Learn more about the term of a senator's service.
If a vacancy occurs due to a senator's death, resignation, or expulsion, the 17th Amendment of the Constitution allows state legislatures to empower the governor to appoint a replacement to complete the term or to hold office until a special election can take place. Typically, a replacement holds office until the next scheduled statewide election.
The Constitution (Article I, section 3) originally provided for senators to be chosen by their state legislature. In 1913, after many years of debate, the 17th Amendment to the Constitution was ratified. It allowed for the direct election of senators , with the provision that a state’s governor, with a legislative mandate, could appoint a senator in the event of a vacancy until the next general election (see Appointments, below).
Learn more about some historic elections.
United States Election, Expulsion, and Censure Cases (book profile)
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