There are two major political groups that usually form government, federally and in the states: the Australian Labor Party and the Coalition which is a formal grouping of the Liberal Party and its minor partner, the National Party. Within Australian political culture, the Coalition is considered centre-right and the Labor Party is considered centre-left. Independent members and several minor parties have achieved representation in Australian parliaments, mostly in upper houses. The Australian Greens are often considered the "third force" in politics, being the third largest party by both vote and membership.