In electoral systems, a wasted vote is any vote which is not for an elected candidate or, more broadly, a vote that does not help to elect a candidate. The narrower meaning includes only those votes which are for a losing candidate or party. A broader definition includes surplus votes for winning candidates who would have won anyway without the wasted vote.
An electoral system which reduces the number bit of wasted votes can be considered desirable on grounds of fairness or on the more pragmatic basis that a voter who feels their vote has made no difference may feel detached from their government or lose confidence in the democratic process. The term "wasted vote" is especially used by advocates of systems like the single transferable vote, or instant-runoff voting which purport to reduce the numbers of such votes.
The term may be considered pejorative by opponents of such systems. Their arguments may either suggest that in any voting system each vote is wasted (unless the result is decided by a single vote), or that no vote is wasted as each one sends a political signal which will be taken into account in preparation for the subsequent election.
In election campaigns, a leading candidate may appeal to voters who support a less-popular candidate to vote instead for the leading candidate for tactical reasons, on the basis that a vote for their preferred candidate is likely to be wasted. In some electoral systems, it may be plausible for less-popular candidates to make similar appeals to supporters of more-popular candidates. In a plurality voting system, the term "wasted vote" is not usually applied to votes for the second-placed candidate, but rather to votes for candidates finishing third or lower. This is a reflection of Duverger's Law, i.e. the institutionalisation of a two-party system.
Consider an election where candidates A, B and C receive 6000, 3100 and 701 votes respectively.
If this is a plurality voting election for a single seat, Candidate A has a plurality of votes and is therefore elected. The wasted votes are:
- All 3801 votes for candidates B and C, since these did not elect any candidate
- In the wider definition, 2899 of the votes for candidate A are wasted, since A would still have won with only 3101 votes. Therefore 6700 out of 9801 votes are wasted.
If the same votes for A, B and C are cast in a d'Hondt method election for 12 seats, then the seats are split 8-4-0 for A-B-C. The wasted votes are:
- All 701 votes for party C, which won no seats.
- In the wide definition, also wasted are:
- 399 votes for A, since A would still have won eight seats with only 5601 votes against 3100 and 701. (With 5600 votes for A, the last seat would go to C).
- 299 votes for B, since only with 2800 votes would B lose the last seat to C.
A majority of votes are always wasted (in the wider sense) in a single-seat election, unless there are exactly two candidates and the margin of victory is exactly one vote. Multi-seat constituencies reduce the number of wasted votes as long as proportional representation is used. (When used with winner-take-all systems, as with the US Electoral College, multi-member constituencies may see the wasted vote reach or exceed 50%).