Dynamics of Strategic Three-Choice Voting

TL;DR

This paper introduces a simple model explaining how two major parties alternate power while a third minority party remains almost perpetually in opposition, based on voters' strategic and ideological voting behaviors.

Contribution

It presents a novel model capturing the dynamics of three-choice voting, explaining the cyclical dominance of two major parties and the persistent minority status of the third.

Findings

Two major parties frequently exchange majority status.

The third minority party remains almost always in the minority.

Voter behavior combining ideological and strategic voting explains observed dynamics.

Abstract

In certain parliamentary democracies, there are two major parties that move in and out of power every few elections, and a third minority party that essentially never governs. We present a simple model to account for this phenomenon, in which minority party supporters sometimes vote ideologically (for their party) and sometimes strategically (against the party they like the least). The competition between these disparate tendencies reproduces the empirical observation of two parties that frequently exchange majority status and a third party that is almost always in the minority.