In-Depth Notes on Spatial Voting Theory and Median Voter Theorem

Overview of Spatial Voting Theory
  • Originates from economics and focuses on a two-party plurality system.
  • Candidates position their policies to attract the median voter for electoral success.
Median Voter Theorem
  • The concept theorizes that parties shift their policies toward the median voter in a one-dimensional left-right political spectrum.
  • Most voters cluster around the center, creating a normal distribution.
  • Winning the median voter enables a party to capture votes from both left and right.
Explanation of Terms
  • Median Voter: The voter located in the middle of the political spectrum, where half the voters are more liberal and half more conservative.
Implications of Median Voter Theorem
  • The theorem suggests that, for parties to win elections, they must appeal to the median voter.
  • Example: If Democrats capture the median voter, they can also attract voters to their left; similarly, Republicans can attract those to their right.
Reasons Why Median Voter Theorem May Fail

  1. Abstinence:

    • Median voters may choose not to vote if they perceive no significant differences between candidates (e.g., “six of one, half a dozen of another”).
    • This leads candidates to shift away from the median to elicit a decision among voters.

  2. Alienation:

    • Candidates may alienate strong partisans by centering too closely to the median voter.
    • Strong partisans play a crucial role in elections; hence, candidates can move away from the center to satisfy them.

  3. Primaries:

    • During primary season, candidates focus on appealing to their party’s base (e.g., "true liberals" vs. "true conservatives") instead of the median voter.
    • Language and rhetoric in this period are often more ideological, diverging from centrist policies.
Election Dynamics
  • General Election Strategy:
    • Candidates pivot towards the median voter after the primaries to appeal to a broader electorate.
  • Influence of Strong Partisans:
    • Strong party ideologues may exert pressure on candidates, restricting their movement toward the median voter.
Case Study: 2008 Presidential Election
  • Analysis by Professor Steven Jesse showed that:
    • Barack Obama and John McCain did not position their policies according to the median voter but rather to the median within their own parties.
    • This illustrates a divergence from the expectations of the median voter theorem, highlighting a focus on co-partisanship instead of centrism.
Conclusion
  • Understanding the dynamics of electoral appeal requires knowledge of how candidates position themselves relative to both median voters and strong partisans.
  • These principles extracted from economics inform political behavior and campaign strategies beyond personal voter-candidate proximity.