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).