Senate majorities have used a complex assortment of rules and practices in recent years to exert greater control over the institution’s decision-making process than at any other point in its history. The principal means by which they establish such control is their ability to block amendments on the Senate floor. A broad selection of recent scholarship captures this dynamic.

The present study, however, considers the ability of the majority leader to use his priority of recognition to block floor amendments in the context of the historical development of the Senate’s amendment trees. When coupled with cloture and employed early in the process, filling the tree may be successful in passing the majority’s preferred bill through the Senate unchanged. At a minimum, the tactic protects members of the majority from having to cast tough votes that could be used against them in their effort to secure re-election.

Yet despite the increased importance of the amendment process to Senate majorities’ efforts to control the agenda, we have, at best, only a limited understanding of how that process developed. Put differently, existing treatments do not account for the role that the amendment process was originally intended to play, the mechanics of how that role was performed and the extent to which it has changed over time. And given the increased controversy surrounding the practice of filling the amendment tree in the Senate today, this represents a significant limitation of the scholarship thus far.

This void can be filled with an analysis of the timing and sequence of the changes in how amendments have been considered on the Senate floor over time and the impact of such changes on the number of amendments simultaneously permitted on legislation. Such an examination of the development of the Senate’s amendment process helps account for the significant institutional change observed in that chamber, as represented by the rapid rise of the practice of filling the amendment tree. Contrary to current practice, the amendment process evolved to facilitate consideration of the Senate’s business in an orderly manner.


Image by Kent Weakley