A Mechanism for Evaluating the Relevance of Credibility Problems in Politics

In this paper we develop a test of whether parties are capable of making credible promises in single-issue elections in which the parties have preferences over policies. Two observations are key: (1) Parties that can commit to specific policies do not adopt platforms that entail large probabilities of losing the election. This is because the adoption of very extreme platforms has the effect of shifting voter’s expectations, and expected policies, away from the party’s most preferred policy. (2) Parties who lack the capacity of making credible commitments are unable to affect voters’ expectations about the policies they will adopt upon reaching office. This is because, absent commitment, voters know that a party will simply adopt its most preferred policy after it wins the election. These observations about voter’s expectations and party behavior form the basis for the test.