"Voting is among the most important public acts of individual Senators. For example, Senators recognize that their decisions often need to be explained to constituents who are interested in knowing why lawmakers voted as they did on various measures or matters. Party leaders, too, understand the importance of voting, for they often try to schedule votes during a time when they believe they can win senatorial support for their objectives. That Senators try never to miss votes is reflected in the high percentage of rollcall votes that they cast. On all recorded votes taken in the chamber, Senators, on average, cast votes over 95% of the time. There are three ways of voting in the Senate: voice, division, and yea and nay (also called rollcall or recorded) votes. Neither voice nor division votes are recognized in the rules of the Senate. Instead, they are permitted by precedent. Senate Rule XII outlines voting procedure in the chamber and explicitly identifies 'the yeas and nays.'."
CRS Report for Congress, 98-227
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