The plurality vote: must it lead to a 2-party system?
Bennett Marsh, Edwin Baeza, Kenneth Brown, Amberlee Carl
- Introduction
- How do we define a “two-party system”? What makes a party a “major party”?
- Brief discussion of plurality and how it is implemented in real elections
- Duverger’s Law - plurality elections tend to encourage 2-party systems
- How it works: what is the mechanism that makes the plurality system lead to 2 dominant parties?
- Tactical Voting - tendency of voters to only vote for the strong parties. No “wasted votes”.
- Fusion of minor parties in an attempt to become stronger
- Real-world examples of the principle occurring in various political systems
- Counterexamples - there exist plurality systems in which there are more than 2 dominant parties
- Converse is not true: 2 party systems may arise even without a plurality election
- How it works: what is the mechanism that makes the plurality system lead to 2 dominant parties?
- Ways of avoiding the collapse into a 2-party system
- Modifications to the standard plurality system
- How a third party can become prominent when 2 dominant parties are already established
- Third parties can exploit weaknesses/mistakes of some major party
- Usually only happens in times of political/social turmoil - e.g. the Civil War
