Unanimous Consent Agreements: Going Along in the Senate

In recent decades, U.S. senators have made increasing use of complex unanimous consent agreements (UCAs) which preclude filibusters by setting a time for a final vote on legislation and which often specify permissible amendments and their proposers. Because of the numerous dilatory tactics permitted in the absence of a UCA, controversial legislation is often doomed unless such an agreement is reached. But in spite of correspondingly strong temptations for opponents to object to unanimous consent requests (UCRs), consent is prevalent. This paper addresses the puzzle with a decision-theoretic model that yields a rather stringent condition for objection to a UCR. Two cases of objection in the Senate are analyzed and found to support hypotheses derived from the model. A concluding discussion considers UCAs as endogenous institutions that permit Senate leaders to induce behavior that appears cooperative but is nonetheless consistent with individual utility maximization.