Two-party system
A two-party system is a party system where two major political parties dominate the government. One of the two parties typically holds a majority in the legislature and is usually referred to as the "majority" or "governing party" while the other is the "minority" or "opposition party". Around the world, the term has different senses. For example, in the United States, Jamaica, and Malta, the sense of "two-party system" describes an arrangement in which all or nearly all elected officials belong to one of the only two major parties, and third parties rarely win any seats in the legislature. In such arrangements, two-party systems are thought to result from various factors like winner-takes-all election rules. In such systems, while chances for third-party candidates winning election to major national office are remote, it is possible for groups within the larger parties, or in opposition to one or both of them, to exert influence on the two major parties. In contrast, in the United Kingdom and Australia and in other parliamentary systems and elsewhere, the term "two-party system" is sometimes used to indicate an arrangement in which two major parties dominate elections but in which there are viable third parties which do win seats in the legislature, and in which the two major parties exert proportionately greater influence than their percentage of votes would suggest.
Democratic Party (United States)
After the War of 1812, the Federalists virtually disappeared and the only national political party left was the Democratic-Republicans. The era of one-party rule in the United States, known as the Era of Good Feelings, lasted from 1816 until the early 1830s, when the Whig Party became a national political group to rival the Democratic-Republicans. However, the Democratic-Republican Party still had its own internal factions. They split over the choice of a successor to President James Monroe and the party faction that supported many of the old Jeffersonian principles, led by Andrew Jackson and Martin Van Buren, became the modern Democratic Party. As Norton explains the transformation in 1828: