Party discipline is the ability of parliamentary members of a political party (often referred to as the caucus or parliamentary party) to get all its parliamentary members to vote in support of policies agreed to by a majority of the parliamentary members or of the party leadership. The party usually appoints a person, commonly referred to as the party whip, whose primary task it is to maintain party discipline and to ensure that parliamentarians vote in accordance with the votes in caucus. In liberal democracies, it usually refers to the control that party leaders have over their caucus members in the legislature. Party discipline is important for all systems of government that allow parties to hold political power because it determines the degree to which the governmental infrastructure will be affected by legitimate political processes.