A coalition government is a cabinet of a government in which several parties cooperate. The usual reason given for this arrangement is that no party on its own can achieve a majority in the parliament. A coalition government might also be created in a time of national difficulty or crisis, for example during wartime, to give a government the high degree of perceived political legitimacy it desires whilst also playing a role in diminishing internal political strife. In such times, parties have formed all-party coalitions (national unity governments, grand coalitions). If a coalition collapses, a confidence vote is held or a motion of no confidence is taken.