Tactical Voting Research Paper

The tendency for voters in single-member districts to avoid wasting their votes on hopeless candidates was noted as long ago as 1869 by the English electoral reformer Henry Droop. But it was Maurice Duverger, writing in the 1950s, who most clearly articulated the systemic consequences of tactical voting. In Duverger’s view, tactical voting arose prominently in single-member plurality elections but hardly at all in proportional representation (PR) systems. He, thus, articulated two main propositions: one, known as Duverger’s Law, asserts that single-member plurality systems promote bipartism; the other, known as Duverger’s Hypothesis, asserts that multimember PR systems promote multipartism. (A third proposition dealt with runoff systems.)

Theoretical work on tactical voting since Duverger has focused on five main topics: (a) tactical voting in electoral systems other than single-member plurality; (b) the logical foundations of Duverger’s Law; (c) the transition from local to global bipartism in Duverger’s Law; (d) tactical voting that deconcentrates, rather than concentrates, the vote; and (e) the role of elites in fomenting tactical voting.

1.1 Tactical Voting Beyond Single-Member Plurality

Reacting to Duverger’s apparent belief that tactical voting was unknown under PR systems, Leys (1959) and Sartori (1968) argued that tactical voting under PR was no different in kind from that found under plurality, differing only in the degree to which it came into play—and, hence, in the degree to which it tended to reduce the number of viable parties. Sartori’s notion of a continuum of systems, from strong (in which tactical voting acts forcefully to depress the number of parties) to feeble (in which tactical voting is largely absent and thus puts little downward pressure on the number of parties), is now standard in the literature.

Subsequent work has made the Leys–Sartori viewpoint more precise, both theoretically and empirically. Steven Reed, for example, has extended Duverger’s Law to Japan’s former electoral system (used from 1925 to 1993, with a brief postwar gap), which gave voters a single vote but used multimember districts. To illustrate Reed’s extension, consider a district with three seats. Candidates expected to place fifth or lower in such districts were sometimes seen as hopeless and were thus deserted by their supporters, essentially reducing the competition to a four-candidate fight for three seats. Reed discovered similar tendencies for elections in four-seat districts to reduce to fivecandidate contests, and for elections in five-seat districts to reduce to six-candidate contests. More generally, under a wide range of electoral systems, the rule is that tactical voting tends to reduce competition in an M-seat district to, at most, M 1 candidates or lists (Cox 1997).

Although political scientists’ main reason for interest in tactical voting is its tendency to concentrate votes locally, hence to restrict party systems nationally, further research into four questions has clarified some limits of this line of reasoning. These questions are considered in the next four subsections.

1.2 Logical Foundations Of Duverger’s Law

First, under what conditions does tactical voting in single-member plurality systems really lead to local bipartism? Recently, various scholars (Cox 1997, Palfrey 1989, Myerson and Weber 1993) have answered this question by articulating conditions under which avoidance of wasted votes in singlemember districts leads, not just to some erosion of support for third-and lower-placed candidates, but to a nearly complete erosion of such support, leaving only two candidates with non-trivial vote shares. Two key conditions identified in this work are that voters be concerned exclusively with the outcome of the current election and that they have ‘rational expectations,’ meaning that their beliefs about the candidates’ likely order of finish in the poll are correct. As empirical circumstances approximate these idealized conditions less closely, one expects less actual erosion of the votes of trailing candidates, and thus less pressure toward local bipartism.

1.3 Local And Global Bipartism

Second, under what conditions does tactical voting in single-member plurality systems lead to global bipartism? The answer is that, although tactical voting does lead under certain circumstances to local bipartism, it does not directly promote bipartism at the national level. Recent work (e.g., Cox 1997) has argued that how local party systems link to form national party systems depends on national-level factors, such as the nature of executive power (presidentialism vs. parliamentarism), rather than on district-specific factors such as tactical voting.

Because local and global bipartism are produced by different factors, they may or may not coincide. Sometimes they do, as in the USA: two parties in each district, two parties nationally. But it is also possible to have local bipartism coupled with national multipartism. This bifurcation between local and global party systems occurs when different parties are viable in different parts of a country, as in India.

1.4 Tactical Voting That Deconcentrates The Vote

Third, does tactical voting always act to concentrate the vote at the local level, hence to restrict the party system? The answer here is ‘no.’ In electoral systems using multimember districts, tactical voters will transfer excess votes from strong candidates, in addition to transferring wasted votes from weak candidates (Tsebelis 1986). This sort of tactical voting deconcentrates the vote, rather than concentrating it, and does not reduce the number of viable parties in the system. Furthermore, in electoral systems using multiple votes, voters may vote for hopeless candidates in order to avoid giving votes to viable candidates who might beat the candidate they really want to win. This sort of tactical wastage of votes again deconcentrates, rather than concentrating, the vote.

1.5 Elite Fomentation Of Tactical Voting

Fourth, is it really voters who play the lead role in tactical voting? Technically, voters that care only about who wins the current election care about their vote only when it breaks a tie (or creates one), because it is only then that their vote affects the outcome. But ties between any trailing candidate and one of the front-runners are much less likely than is a tie between the top two. Thus, purely instrumental voters vote for whichever of the two front-runners they most prefer, as their votes are then most likely to do some good.

But if citizens think this way about voting, why would they vote at all? The chances of a single vote actually affecting the outcome are tiny, which suggests that the purely instrumental voter might just as well stay home and save a trip to the polls.

Scholars who argue along these lines have suggested that the key actors in generating tactical voting are parties and candidates—who have more at stake in an election and can take actions that potentially swing many votes, hence have a reasonable chance of affecting the outcome. To date, however, there is no published elaboration of how such elite-led tactical voting would differ from the grass roots tactical voting envisioned in most of the literature.

2. Tactical Voting To Affect Government Formation

The second broad category of tactical voting is that by which voters seek to secure a better allocation of ministerial portfolios. Portfolio-maximizing tactical voting has three different subcategories.

One subcategory is strategic sequencing—or voting to affect which party gets the first opportunity to form a government. This sort of tactical voting may have been important in Israeli elections prior to the reform of the rules for electing the prime minister.

A second subcategory is strategic balancing—or voting so as to prevent any single party or coalition from securing control of all bodies in a system of separated powers. This sort of tactical voting is argued to play a role in German and US elections. In the US case, the argument is that some voters vote for one party’s presidential candidate but the other party’s congressional candidate, intentionally seeking to deny either party control of both policy-making branches of government (Alesina and Rosenthal 1995). In the German case, a similar argument has been made to explain the opposition’s consistent success in midterm state elections, which determine control of the upper house at the federal level (Lohmann et al. 1997).

A third subcategory is strategic threshold insurance—or voting to keep a prospective coalition partner’s vote above a legally defined threshold to qualify for PR seats. This sort of tactical voting has clearly been important in German elections and may become so in other countries that have parties hovering around the relevant threshold values.

3. Tactical Voting As Protest

The third broad category of tactical voting is protest voting—voting against one’s most-preferred party, even though it stands a good chance of winning, in order to chasten it and modify its behavior in future. Protest voting fits the general definition of tactical voting given at the outset of the paper, if one includes the result of future elections in the ‘better outcome’ that the voter seeks. As an example, consider a voter who prefers that party A win the seat in a singlemember district but is nonetheless unhappy with some aspects of A’s performance. Such a voter may try to ‘send a message’ by either abstaining, casting an invalid vote, voting for a third party, or (if the voter is confident that A will nonetheless win) voting for A’s main opponent. The point is not to defeat A, but to reduce A’s margin of victory and hopefully scare it into better behavior in future.

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