Political parties serve important functions in American politics such as linking citizens' concerns to government, picking candidates, running campaigns, and coordinating policymaking. There are three components of a political party: the party in the electorate consisting of voters, the party organization made up of local and national officials and staff, and the party in government comprising elected representatives. Throughout American history, political parties have undergone periods of dominance by one party known as party eras, which are sometimes punctuated by critical elections that cause party realignments. While third parties rarely win elections, they can influence the major parties by bringing new issues and constituencies into politics.