BEYOND COMMITTEE CONTROL

Abstract

In this article we test several hypotheses—committee unity, committee chairman support, majority leader support, minority leader support, timing during the session, and type of policy issue—that previous research identifies as explanations of variation in the success or failure of floor amendments. We find that committee unity is the most important variable in all contexts—if the committee is unified for or against an amendment, its position is almost certain to prevail on the floor. Party leaders, also, often exert significant independent effects on the success of floor amendments. The extent of their influence, however, varies with the context and with the degree of committee unity. And even when party leaders exert significant independent effects, their support for a floor amendment results in very small changes in the probability of passage, except when the committee reporting the bill is divided. Although committees may dominate the amending process if they are unified, achieving unity on the floor may be beyond committee control to manipulate. Because committees are usually divided on the floor, influence over policymaking in Congress is typically shared among different institutional actors.