Casting vote

A casting vote is a vote which may be exercised (usually in addition to his or her normal vote as a member of the body, if he or she has one) by the presiding officer of a council or legislative body, or of any committee, to resolve a deadlock and which can be exercised only when such a deadlock exists. Examples of officers who hold casting votes are the Speaker of the British House of Commons and the President of the United States Senate (an ex-officio role of the Vice President of the United States).

In some legislatures, a casting vote may be exercised however the presiding officer wishes. An example is the Vice President of the United States, who may exercise his casting vote in the Senate according to his party affiliation or according to his own personal beliefs. By virtue of the Vice President's casting vote, when the Senate as elected is equally divided between two parties, the Vice President's party automatically becomes the official majority party in the Senate. The exercise of the Vice President's casting vote has become increasingly rare throughout American history as the size of the Senate has grown from 26 to 100 and ties have become less probable.

In some other legislatures, by contrast, a casting vote can only be exercised according to strict rules or conventions. For example, the Speaker of the British House of Commons is expected by constitutional convention to follow Speaker Denison's rule, i.e. to vote to allow further discussion, if this is possible, and otherwise to vote in favour of the status quo.

The concept of a casting vote is not used in Robert's Rules of Order.

Under some rules of parliamentary procedure, notably Robert's Rules of Order, the presiding officer does not have a casting vote in the way it is normally understood as a means to break ties. Instead, he or she has a normal vote, but exercises it only after other members have voted, and only if it would make a difference. This allows the presiding officer to vote against a motion to bring it to a tie and defeat it (for instance, if the vote is 50-49, the presiding officer could defeat the vote by voting against) in addition to breaking a tie by voting in favour. The intent behind this rule is to give the presiding officer the same voting rights as other members while preserving their impartiality whenever possible, by not having them vote unless it would change the outcome.

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