Amendments , Covering , and Agenda Control : The Politics of Open Rules ∗

Agenda control in legislative bodies is an important and complicated topic. Frequently, the discussion of agenda control is limited to procedures that restrict what may be considered on the floor, as exemplified by “closed rules” in the United States House of Representatives. In this paper, we expand the discussion of agenda control by considering the effects of predetermining part of an amendment agenda. Empirically, this type of agenda control is practiced through the use of an “open” rule that provides a privileged position on the voting agenda to one or more amendments. By defining a binary relation for general collective choice situations, the needing relation, we characterize the feasibility of agenda control under open rules with sophisticated legislators. We demonstrate an equivalence between a notion of majoritarianism and outcomes that do not depend upon agenda manipulation to be selected under an open rule. Specifically, we demonstrate that this set of outcomes is the “Banks set of the Banks set.” ∗Some of the material in this paper was previously circulated under the title “Needing and Covering.” †Assistant Professor, Department of Government & Institute for Quantitative Social Science, Harvard University, Email: [email protected]. ‡Assistant Professor, Department of Government & Institute for Quantitative Social Science, Harvard University, Email: [email protected].