Corruption and power in democracies

We study the implications of Acton's dictum that power corrupts when citizens vote (for three parties) and governments then form in a series of elections. In each election, parties have fixed tastes for graft, which affect negotiations to form a government if parliament hangs; but incumbency changes tastes across elections. Our model entails various plausible predictions about long-run patterns of government. Acton's dictum results in possible government turnover, and in different predictions about possible government composition: for example, that the grand coalition may form.