Texas A&M University (TAMU) POLS207 State and Local Government Exam 2 Practice Exam

Duverger's Law posits that in electoral systems with single-member districts and plurality voting (where the candidate with the most votes wins), a two-party system is likely to develop. This phenomenon occurs due to the mechanical and psychological effects of the electoral system.

Mechanically, in single-member districts, votes for candidates outside of the two leading parties tend to be wasted. Voters recognize that their preferred candidate from a smaller party has little chance of winning, which leads them to support one of the two major candidates instead. This creates a cycle where the two leading parties dominate elections while smaller parties struggle to achieve representation.

Psychologically, voters tend to perceive a two-party system as more stable and more responsive to their needs. As a result, individuals might align their political preferences with one of the two main parties, reinforcing this dynamic.

Thus, Duverger's Law suggests that the structure of the electoral system significantly influences the party system, favoring the emergence of a two-party system in single-member district systems.