This article identifies for the first time systematic performance differences between younger and older democracies and argues that these are driven by the inability of political competitors to make broadly credible preelectoral promises to voters. Younger democracies are more corrupt; exhibit less rule of law, lower levels of bureaucratic quality and secondary school enrollment, and more restrictions on the media; and spend more on public investment and government workers. This pattern is exactly consistent with the predictions of Keefer and Vlaicu (n.d.). The inability of political competitors to make credible promises to citizens leads them to prefer clientelist policies: to underprovide nontargeted goods, to overprovide targeted transfers to narrow groups of voters, and to engage in excessive rent seeking. Other differences that young democracies exhibit, including different political and electoral institutions, greater exposure to political violence, and greater social fragmentation, do not explain, either theoretically or empirically, these policy choices.