The document discusses the two-party system in the United States. It provides reasons for the dominance of the two-party system, including historical precedent and the electoral system. It also briefly discusses multiparty and one-party systems. Additionally, it covers factors that influence party membership and outlines the history of political parties in the US in four major eras from 1800 to today. Finally, it defines types of minor parties and their importance in influencing and drawing attention to issues.