What is your agenda?’ How political parties use commitments to credibly change their issue priorities

Policy commitments are risky to make for political parties, because voters will punish them, if they break them after the election. Yet, parties make hundreds of commitments, and the number has even increased in recent decades. Why do parties commit themselves to their future behaviour to such a high extent? In this paper, I argue that parties are particularly likely to use a policy committing strategy, when they have increased their emphasis on an issue from the previous election. By making commitments, parties try to regain credibility by increasing the electoral costs of ignoring this issue after the election. In this way, parties use commitments to trade future flexibility in the policy-making process for credibility among the electorate in the present. I test this argument by manually coding tens of thousands quasi-sentences in election manifestos from a diverse set of countries and over several elections. Empirically, I show that parties use the policy committing strategy to a higher extent when they have increased the saliency of an issue. These results have important implications for party strategies, issue competition, and policy-making.