Committee protocols typically involve a deliberation stage in which members try to influence and convince other regarding the “right” decision. Beyond information exchange, such deliberations also aim to affect the preferences and the votes of other members. Using a model of social influence, we demonstrate how deliberation procedures affect the voting outcome and how different protocols of consultation by committees’ chairs may affect their decisions. We then analyze the ability of a “designer” to control the deliberation protocol and to manipulate (...) the deliberation procedure to increase the probability that the outcome he favors will be selected. (shrink)