The Two-Party System in America: An Exploration of Duverger’s Law

Introduction to Duverger’s Law

• Duverger’s Law developed by Maurice Duverger in the 1950s.
• Suggests voting method influences the number of political parties.
• Not a result of disinterest in third parties.

Key Factors of Duverger’s Law

1. Vote Requirement for Winning a Seat
   • Threshold: How many votes are needed to win?
   • Winner-takes-all system: Single-member districts.
2. Voter Encouragement
   • Are voters encouraged to vote for favorites, even if unlikely to win?

Plurality Voting in America

• Characteristics
  • Single-winner voting method.
  • Elects through single-member districts.
  • "Winner-takes-all" nature.
• Challenges for Third Parties
  • Hard for smaller parties to gain representation.
  • Voter psychology discourages votes for less popular candidates due to "Spoiler" effect.

Alternative Voting Methods

Approval Voting

• Description
  • Single-winner method.
  • Allows voting for multiple candidates.
• Effects on Duverger’s Factors
  • Addresses psychological barrier by allowing votes for favorites without compromising.
  • Provides accurate support measure for third parties.
  • Still within a winner-takes-all system, high threshold remains.

Proportional Representation

• Mechanism
  • Combines districts into multi-winner districts.
  • Seats assigned based on vote proportions rather than top vote-getters.
• Advantages
  • Lowers threshold for winning seats.
  • Encourages voting for favorite candidates.
  • Effectively addresses both aspects of Duverger’s Law.
  • Increases representation for smaller parties.

Summary and Conclusion

• Plurality Voting
  • Fosters two-party dominance.
  • Hampers third-party success.
• Approval Voting
  • Helps reflect third-party support.
  • Still doesn’t solve "winner-takes-all".
• Proportional Representation
  • Facilitates a multi-party system.
  • Lowers entry barriers for smaller parties.
• Conclusion
  • Duverger’s Law demonstrates how voting systems shape party structures.
  • Other factors exist, but voting methods are crucial.

Further Learning

• Center for Election Science - Electology.org
  • Resources on democracy and voting methods.