Senate seats become vacant for a variety of reasons — the Senator dies in office, resigns in disgrace or resigns to assume another position, usually, an elected or appointed government position.

What happens when a Senator dies in office or resigns? How is the replacement handled?

Procedures for electing Senators are outlined in Article I, Section 3 of the U.S. Constitution, as later amended by paragraph 2 of the Seventeenth (17th) Amendment. Ratified in 1913, the 17th Amendment not only changed how Senators are to be elected (direct election by popular vote) but it also outlined how Senate vacancies are to be filled:

When vacancies happen in the representation of any State in the Senate, the executive authority of such State shall issue writs of election to fill such vacancies: Provided, That the legislature of any State may empower the executive thereof to make temporary appointments until the people fill the vacancies by election as the legislature may direct.

What Does This Mean in Practice?

The U.S. Constitution grants the state legislatures the power to determine how U.S. Senators are to be replaced, including empowering the chief executive (the governor) to make these appointments.

Some states require a special election to fill a vacancy. A few states require the governor to appoint a replacement of the same political party as the previous incumbent. Typically, a replacement holds office until the next scheduled statewide election.

From the Congressional Research Service:

Prevailing practice is for state governors to fill Senate vacancies by appointment, with the appointee serving until a special election has been held, at which time the appointment expires immediately. In the event a seat becomes vacant between the time of a general election and the expiration of the term, however, the appointee usually serves the balance of the term, until the next regularly scheduled general election. This practice originated with the constitutional provision that applied prior to the popular election of senators, under which governors were directed to make temporary appointments when state legislatures were in recess. It was intended to ensure continuity in a state’s Senate representation during the lengthy intervals between state legislative sessions.

Exceptions or Where Governors Do Not Have Unlimited Powers

Alaska, Oregon, and Wisconsin do not allow the governor to make interim appointments; state laws require a special election to fill any Senate vacancy.

Oklahoma also requires that Senate vacancies be filled by special elections, with an exception. If the vacancy occurs after March 1 of any even-numbered year and the term expires the following year, no special election is held; rather, the governor is required to appoint the candidate elected in the regular general election to fill the unexpired term.

Arizona and Hawaii require the governor to fill Senate vacancies with a person affiliated with the same political party as the previous incumbent.

Utah and Wyoming require the governor to select an interim senator from a list of three candidates proposed by the state central committee of the political party with which the previous incumbent was affiliated.

In the event of a Senator’s death, his or her staff continue to be compensated for a period not exceeding 60 days (unless the Senate Committee on Rules and Administration determines that more time is needed to complete the closing of the office), performing duties under the direction of the Secretary of the Senate.