Editing By-election (section)

== In multi-member constituencies ==

When one seat in a [[Multi-member district|multi-member constituency]] becomes vacant, the consequences vary. For example, a by-election may be held to fill just the vacancy, all the seats in the constituency could be contested in the by-election, or the vacancy could be filled by other means.

Typically, [[party-list proportional representation]] systems do not hold by-elections. Instead, the most successful unelected candidate named on the vacator's list fills the vacancy automatically. However, [[Turkey]] is an exception, as it holds by-elections when too many seats become vacant in the parliament (as in [[1986 Turkish parliamentary by-elections|1986]]) or a repeat vote has to be held (as in [[2003 Siirt Province by-election|2003]]).

In multi-member district systems that do not employ party lists – [[single transferable vote]], [[single non-transferable vote]] and [[plurality at-large]] – vacancies may be filled by a by-election. This is done, for example, in the [[Dáil]] of the [[Republic of Ireland]] (STV), in the [[Parliament of Vanuatu]] (SNTV), and in the [[Senate of the Philippines]] (Pl. AL). In those systems, alternatives to holding a by-election include:

# re-determining the election results with the vacators disregarded, as in [[Tasmania]]<ref>{{Cite web |title=Tasmania's Hare-Clark Electoral System |url=http://www.electoral.tas.gov.au/pages/ElectoralInformation/HareClark.html |url-status=dead |archive-url=https://web.archive.org/web/20110423035117/http://www.electoral.tas.gov.au/pages/ElectoralInformation/HareClark.html |archive-date=2011-04-23}}</ref> or the [[Australian Capital Territory]],<ref>{{Cite web |title=Casual Vacancies in the Legislative Assembly |date=25 March 2021|url=http://www.elections.act.gov.au/elections_and_voting/casual_vacancies_in_the_legislative_assembly}}</ref>
# keeping the seat vacant until the next [[general election]]. This usually occurs if a vacancy arises shortly before a planned general election (within six months in New Zealand).
# nominating another candidate with the same affiliation as the former member, such as [[European Parliament]] seats in the Republic of Ireland.

For the [[Australian Senate]] (in which each state forms a multi-member constituency elected via [[single transferable vote]]), the state parliament appoints a replacement in the event of a vacancy; in 1977 a referendum amended the Constitution to require that the person appointed must belong to the same political party (if any) as the Senator originally elected to that seat. The states with an [[upper house]] elected via STV (NSW, Victoria, and South Australia) use the same method, except for Western Australia, which holds a recount of ballots to determine the new winner, with sitting members retaining their seats.