Ideal deliberative democracy seeks to employ unbiased moderators. Yet, a large literature in the field of mediation suggests the elusiveness of perfect neutrality. Our study thus addresses the following question: when moderators of deliberations express their own views – even in a limited manner – can they change the preferences of participants? Using a novel experimental design in a real deliberative decision-making process, we find that moderators can significantly influence the attitudes and behaviors of participants by expressing views in a constrained manner. The results of our study have implications for refining epistemic conceptions of deliberative democracy and for designing more precise empirical investigations of the effects of deliberative processes on attitudes and behavior. The results also warn of a simple mechanism by which interest groups might hijack the deliberative decision-making processes used in community driven development projects all over the world.