A presiding officer is needed in all legislatures to impartially oversee the procedures of debate. Most commonly this officer is called the speaker especially in unicameral parliaments (those with one house) or in the Lower Houses of bicameral parliaments. The presiding officer of an Upper House or second chamber is not normally called the speaker, but most commonly president, chairman or chair. In some countries with a republican, or non-hereditary constitution, the vice-president of the country is sometimes, by virtue of the position, the presiding officer of the second chamber.