	Introduction

Unanimous consent agreements are special orders of the Senate that are agreed to without objection by the chamber's membership. Whereas the Senate Rules permit virtually unlimited debate, and very few restrictions on the right to offer amendments, these agreements usually limit time for debate and the right of Senators to offer amendments. Based on trust, and reached after often protracted negotiations, unanimous consent agreements are the equivalent of "binding contracts" that can only be changed or modified by unanimous consent. In the early 1900s, the Senate took modest steps to reduce some of the confusion associated with unanimous consent agreements, such as requiring these accords to be submitted in writing to the desk, read to the chamber, and "printed on the title page of the daily calendar of business as long as they were operative." First, could these agreements be changed or modified by another unanimous consent agreement? Two critical portions of the rule stipulate that (1) unanimous consent agreements are orders of the Senate, which means that the presiding officer is charged with enforcing their terms; and (2) the Senate, by unanimous consent, could change a unanimous consent agreement. The contemporary Senate regularly operates via the terms of unanimous consent agreements.
Unanimous consent agreements are fundamental to the operation of the Senate. The institution frequently dispenses with its formal rules and instead follows negotiated agreements submitted on the floor for lawmakers' unanimous approval. Once entered into, unanimous consent agreements can only be changed by unanimous consent. Their objectives are to waive Senate rules and to expedite floor action on measures or matters. Typically, these accords (sometimes called time-limitation agreements) restrict debate and structure chamber consideration of amendments.
Given their importance to chamber operations, it is worthwhile to understand the background, or origin, of unanimous consent agreements. The purpose of this report is to examine how and why these informal agreements became special orders of the Senate enforceable by the presiding officer. This report will be updated as circumstances warrant. Further information on unanimous consent agreements can be found in CRS Report 98-225, Unanimous Consent Agreements in the Senate, by [author name scrubbed]; CRS Report RS20594, How Unanimous Consent Agreements Regulate Senate Floor Action, by [author name scrubbed]; and CRS Report 98-310, Senate Unanimous Consent Agreements: Potential Effects on the Amendment Process, by [author name scrubbed].