Presiding Officer of the United States Senate
|This article is part of a series on the|
|United States Senate|
|History of the United States Senate|
|Politics and procedure|
The Presiding Officer is the person who presides over the United States Senate and is charged with maintaining order and decorum, recognizing members to speak, and interpreting the Senate's rules, practices and precedents. The Presiding Officer is a role, not an actual office; whoever is presiding at the time is the Presiding Officer.
Who acts as Presiding Officer 
The presiding officer may be the President of the Senate, who under Article One of the United States Constitution is the Vice President of the United States and may vote when the Senate is "equally divided" - that is, when a tie occurs. While some early Vice Presidents regularly presided over the Senate, in modern times the Vice President has only actively presided over the chamber when it is anticipated that he may be able to use his casting vote to break a tie, or on ceremonial occasions, such as the counting of electoral votes following a presidential election and the swearing-in of new members.
The President pro tempore (a Senator elected to the post by the Senate at the beginning of each Congress, which since World War II by custom has been the most senior Senator of the majority party) is nominally responsible for presiding over the Senate "in the Absence of the Vice President, or when he shall exercise the Office of the President of the United States" (Article I, Section 3, Clause 5). More typically, junior senators of the majority party designated by the President pro tempore preside over the chamber.
An exception to this pattern is when the Senate hears the impeachment trials of the President of the United States, in which the Chief Justice of the United States is the presiding officer. This has occurred only twice, during the impeachment trial of Andrew Johnson in 1868 (in which Chief Justice Salmon P. Chase presided) and that of Bill Clinton in 1999 (in which Chief Justice William H. Rehnquist presided).
Manner of address 
The presiding officer is usually addressed as "Mr. President" or "Madame President." One exception is during impeachment trials of the president; the Chief Justice was referred to as "Mr. Chief Justice" both in 1868 and in 1999 while presiding over the Senate.
During joint sessions of Congress in which the President of the United States is giving the address, practices have varied as to how the President refers to the Vice President. President Barack Obama and his immediate predecessor George W. Bush have addressed the Vice President as "Vice President Biden" (in 2010) and "Vice President Cheney" (in 2008 and several previous years), or as "Mr. Vice President" (George W. Bush in 2001). However, earlier presidents referred to the Vice President as "Mr. President" while addressing a joint session of Congress; Eisenhower, for instance, did so in 1960, and George H. W. Bush did so in 1991.
See also 
- Speaker of the United States House of Representatives, the presiding officer of the United States House of Representatives