What happens if a Senator leaves their position before their term is up?

In Plain English

If a Senator's position becomes vacant before their term is finished, here's what generally happens:

  • State Senators: The Parliament of the State that the Senator represented chooses a replacement to fill the position until the end of the original Senator's term. If the State's Parliament isn't meeting at the time, the State's Governor can appoint someone to temporarily fill the role until the Parliament can choose a permanent replacement.
  • Territory Senators: The Legislative Assembly of the Territory chooses a person to hold the place until the expiration of the term. But if the Legislative Assembly is not in session when the vacancy is notified, the Chief Minister for the Australian Capital Territory or the Administrator of the Territory may appoint a person to hold the place until the expiration of 14 days from the beginning of the next session of the Legislative Assembly or the expiration of the term, whichever first happens.
  • Political Party: If the Senator was publicly known to be a member of a political party, the replacement usually has to be a member of that same party, if one is available.
  • Notification: The President of the Senate notifies the relevant authorities (the State Governor, or the Chief Minister or Administrator of the Territory) about the vacancy.

Detailed Explanation

Section 15 of the Commonwealth of Australia Constitution Act deals with "Casual vacancies" for senators. If a senator's place becomes vacant before their term expires, the following process is invoked:

  1. State Senators:

    • The Houses of Parliament of the State (sitting and voting together) which the senator represented, choose a person to hold the place until the expiration of the term Commonwealth of Australia Constitution Act.
    • If the Parliament of the State is not in session when the vacancy is notified, the Governor of the State, with the advice of the Executive Council, may appoint a person to hold the place temporarily. This appointment lasts until either:

  2. Territory Senators:

    • According to the Commonwealth Electoral Act 1918, if a senator for the Australian Capital Territory or the Northern Territory leaves office early, the relevant Territory's Legislative Assembly chooses a replacement. If the Assembly isn't meeting, the Chief Minister (for the ACT) or the Administrator (for the Northern Territory) can appoint a temporary replacement until the Assembly meets.
    • For other territories, a joint sitting of the Senate and House of Representatives chooses the replacement, or the Governor-General can make a temporary appointment if Parliament isn't in session Commonwealth Electoral Act 1918.

  3. Political Party Representation:

  4. Notification of Vacancy:

    • Section 21 of the Commonwealth of Australia Constitution Act states that whenever a vacancy occurs in the Senate, the President of the Senate (or the Governor-General if there is no President or the President is absent from the Commonwealth) must notify the Governor of the State which the senator represented.
    • According to the Commonwealth Electoral Act 1918, for Territory senators, the President of the Senate notifies the Chief Minister (for the ACT), the Administrator (for the Northern Territory), or the Governor-General (for other territories) of the vacancy.

  5. Certification: