Tactical voting: Difference between revisions
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* A broader type (also known as '''turkey-raising''' or the '''pied-piper strategy''') which can happen in two-round systems.<ref>{{Cite news |last=Linskey |first=Annie |date=2022-09-13 |title=Democrats spend tens of millions amplifying far-right candidates in nine states |language=en-US |work=Washington Post |url=https://www.washingtonpost.com/politics/2022/09/12/democrats-interfere-republican-primaries/ |access-date=2023-10-02 |issn=0190-8286}}</ref><ref>{{Cite web |last=Norton |first=Ben |date=2016-11-10 |title=How the Hillary Clinton campaign deliberately "elevated" Donald Trump with its "pied piper" strategy |url=https://www.salon.com/2016/11/09/the-hillary-clinton-campaign-intentionally-created-donald-trump-with-its-pied-piper-strategy/ |access-date=2023-10-02 |website=Salon |language=en}}</ref> This broader type requires three candidates to explain: "A", "B" and "X". Let's say that voters are asked to choose (in the first round of an election) between "B" and "X". Voters who prefer "A" in the second round of the election may hope to have other voters vote for "the turkey" (candidate "X") who cannot beat "A", rather than see candidate "B" advance to the second round of the election, and may vote for "X" over "B" if they are allowed.<ref>{{Cite web |title=[EM] St. Louis and Pushover (Re: Reply to Rob regarding RCV) |last=Munsterhjelm|first=Kristofer|url=http://lists.electorama.com/pipermail/election-methods-electorama.com/2023-October/004961.html |access-date=2023-10-02 |website=lists.electorama.com}}</ref>
=== Free
[[Free riding]] is a form of tactical voting which affects any [[Multi-Member System]] that has a mechanisms to increase the level of [[Proportional representation]]. The strategy is to lower your endorsement for candidates which you expect to be elected without your support. This allows more of your vote power to go into electing other candidates, because the voting method takes less of your voting power.
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However, the extent to which tactical voting affects the timbre and results of the campaign varies dramatically from system to system: see below.
== Strategy-resistant voting methods ==
While no deterministic voting method may be strategy-free, the degree that they reward strategy differ greatly. [[Plurality voting]] and the [[Borda count]] often reward tactical voting, while [[Condorcet-IRV hybrid methods]] are considerably more robust.<ref name="Green 2001 four">{{cite journal | last=Green-Armytage |first=James |title=Four Condorcet-Hare hybrid methods for single-winner elections | journal=Voting matters | issue=29 | page=8 | year=2011 | url=http://www.votingmatters.org.uk/ISSUE29/I29P1.pdf}}</ref>
François Durand found that for voting methods passing [[Informed majority coalition criterion|a weak form of the majority criterion]], modifying the method to elect the [[Condorcet winner]] whenever one exists can never increase the susceptibility to strategy. He also found that, given an independence assumption, asking for more information than ranks can't unlock higher levels of strategy resistance. Durand thus argues that a search for the most strategy-resistant voting method can be restricted to ranked methods that pass the Condorcet criterion.<ref name="Durand Mathieu Noirie 2014 v533">{{cite web | last=Durand | first=François | last2=Mathieu | first2=Fabien | last3=Noirie | first3=Ludovic | title=Making a voting system depend only on orders of preference reduces its manipulability rate | website=Sorbonne Université | date=2014-06-17 | url=https://hal.sorbonne-universite.fr/hal-01009136/ | access-date=2024-04-21}}</ref>
A variety of criteria have been devised to indicate forms of strategy resistance. See, for instance, [[dominant mutual third burial resistance]].
== Examples in real elections ==
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=== Predisposition to sincerity ===
Some experiments have found that voters tend to behave sincerely more often than the instrumentally rational model indicates. In an experiment designed to have a low barrier to sophisticated voting, Herzberg and Wilson found that only 20%-40% of the voters made use of the opportunity; the rest voted sincerely.<ref name="Herzberg Wilson 1988 pp. 471–486">{{cite journal | last=Herzberg | first=Roberta Q. | last2=Wilson | first2=Rick K. | title=Results on Sophisticated Voting in an Experimental Setting | journal=The Journal of Politics | publisher=
Blais and Nadeau use a two-step analysis procedure to argue that 30% of the voters who would have benefited from strategic voting in the 1988 Canadian election actually did vote strategically.<ref name="Blais Nadeau 1996 pp. 39–52">{{cite journal | last=Blais | first=André | last2=Nadeau | first2=Richard | title=Measuring strategic voting: A two-step procedure | journal=Electoral Studies | publisher=Elsevier BV | volume=15 | issue=1 | year=1996 | issn=0261-3794 | doi=10.1016/0261-3794(94)00014-x | pages=39–52}}</ref> They furthermore reason that tactical voting is more prevalent if the voters have only a weak intensity of preference for their first choice over their second, or if the election is a close race between their second and third choice.
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== Definitions ==
{{
'''Frontrunner/viable candidate''': A candidate expected to have a significant chance of winning.
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Due to the especially deep impact of tactical voting in [[first past the post]] electoral systems, some argue that systems with three or more strong or persistent parties become in effect forms of [[disapproval voting]], where the expression of disapproval, to keep an opponent out of office overwhelms the expression of approval, to approve a desirable candidate. [[Ralph Nader]] refers to this as the "least worst" choice, and argues that the similarity of parties and the candidates grows stronger due to the need to avoid this disapproval.
Sirin Botan et al. showed that every Condorcet method of a particular type sometimes incentivizes the creation of Condorcet cycles when there's a sincere [[Condorcet winner]]. The types covered are Condorcet methods that only use pairwise defeat information and don't always tie when there's no Condorcet winner. <ref name="Botan Endriss 2021 pp. 5202–5210">{{cite journal | last=Botan | first=Sirin | last2=Endriss | first2=Ulle | title=Preserving Condorcet Winners under Strategic Manipulation | journal=Proceedings of the AAAI Conference on Artificial Intelligence | publisher=Association for the Advancement of Artificial Intelligence (AAAI) | volume=35 | issue=6 | date=2021-05-18 | issn=2374-3468 | doi=10.1609/aaai.v35i6.16657 | pages=5202–5210}}</ref> This category includes, among others, [[ranked pairs]] and [[Copeland's method]], but not [[Smith//IRV]] or [[Condorcet-cardinal hybrid methods]].
There are arguments about the best voting strategy to take in different systems, but the general consensus is:
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=== Voting for the lesser of two evils ===
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Much voting strategy revolves around a voter deciding whether to back one of the frontrunners or not; this often reduces further to deciding which of 2 frontrunners to back, which results in essentially a [[head-to-head matchup]] between the two. This is often referred to as deciding whether to "vote for the lesser of two evils or waste your vote". One of the goals of voting reform is to allow voters to be able to be as sincere as possible in expressing their preference for nonviable candidates.
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