We present a model of policy development in which competing factions have different ideologies, yet agree on certain common objectives. Policy developers can appeal to a decision maker by making productive investments to improve the quality of their proposals. These investments are specific to a given proposal, which means that policy developers can potentially obtain informal agenda power. Competition undermines this agenda power, forcing policy developers to craft policies that are better for the decision maker. This beneficial effect is strongest if policy developers have divergent ideological preferences, because their intense desire to affect policy motivates them to develop higher-quality proposals.