(politics) the two major political parties in the United States. American government functions almost entirely through the party systemNa voluntary organization of voters in which most registered voters in the US give their allegiance to one of these two major parties. The two-party systemhas the advantage of making for stability of government by preventing the formation of a variety of minority parties or factions, but its greatest disadvantage is that often there is no clear-cutline of demarcation between the ideals and objectives of the two parties. —Conquest of Chaos Approved Glossary (8.7.92)