How Important is the Credibility Problem in Politics? Evidence from State-Level Abortion Legislation

This paper proposes a simple mechanism for evaluating the relevance of credibility problems in politics. If candidates are capable of making credible policy promises, we will not expect them to systematically adopt platforms that entail large probabilities of losing an election. This is because the adoption of very extreme platforms has the effect of shifting expected policies systematically away from their ideal points. For candidates who lack the capacity of making credible commitments, in contrast, policy platforms are simply a reflection of their preferences, which may well be very extreme. I show that this fact implies that when politicians are credible the correlation between candidates preferences and expected policies will always be positive, whereas when they lack credibility the correlation can be negative. Empirical tests on a panel of US abortion preferences and legislation show that the correlation between the preferences of party constituents and enacted policies is consistently negative, a result that strongly suggests the existence of significant credibility problems.