Subject to Debate
The Senate's tradition of unlimited debate dates back to the first Congress, when a handful of senators used stalling tactics to defeat a proposal to move the capital from New York City to Philadelphia. Since then, the practice of unlimited debate has been one of the most cherished rights in the Senate, and is the most distinguishing characteristic that sets it apart from the House of Representatives.
What's a Filibuster?
When unlimited debate is used to defeat a bill, it is called a filibuster. Popularized by Jimmy Stewart in the movie Mr. Smith Goes to Washington, filibustering typically involves endless speech on the Senate floor by a member or members, and may also include a series of delaying tactics such as calling for consecutive roll calls, raising points of order, and offering nongermane (not relevant) amendments.
Filibustering is a highly effective mechanism for senators to defeat legislation or win concessions on nonrelated issues, especially if employed late in the session when there is insufficient time to break it. If timed correctly, the mere threat of a filibuster can be an effective negotiating tool. In some cases, senators will block legislation simply by asking their party leaders not to schedule the matter. This is called a hold, and using the hold is a custom honored by Senate leaders. In the last few years, the use of holds has been modified and curtailed.
In 1917, at the urging of President Woodrow Wilson, the Senate amended its rules to provide a means for cutting off debate. Rule 22 (or cloture, as it is known) is invoked when three-fifths of the members present vote in favor of ending debate. Once cloture is adopted, senators have thirty hours of remaining debate before a final vote is taken.
The late Senator Strom Thurmond of South Carolina holds the record for the longest solo filibuster. He spoke for twenty-four hours and eighteen minutes against the Civil Rights Act of 1957. Throughout the late 1950s and early '60s, southern Democrats repeatedly filibustered a series of civil rights initiatives until cloture was finally invoked and the historic Civil Rights Act of 1964 became law.
Unanimous Consent Agreements
One way the Senate avoids the cycle of endless filibusters and cloture is through unanimous consent agreements. These are agreements that the majority and minority leaders make regarding the length of debate, the number and types of amendments that can be offered, and the time of final vote for a particular piece of legislation. As its name suggests, a unanimous consent agreement requires the full consent of every senator present — one “nay” vote kills the agreement. Most Senate business is conducted according to unanimous consent agreements.