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.
Dominant-party system
Sub-national entities are often dominated by one party due the area's demographic being on one end of the spectrum. For example, the current elected government of the District of Columbia has been governed by Democrats since its creation in the 1970s, Bavaria by the Christian Social Union since 1957, Madeira by the Social Democrats since 1976, and Alberta by Progressive Conservatives 1971–2015. On the other hand, where the dominant party rules nationally on a genuinely democratic basis, the opposition may be strong in one or more subnational areas, possibly even constituting a dominant party locally; an example is South Africa, where although the African National Congress is dominant at the national level, the opposition Democratic Alliance is strong to dominant in the Province of Western Cape.
Federally, a multi-party system exists, although only two federal parties have ever held power, the Conservative Party and the Liberal Party. However, in some provinces, a party holds hegemonic status over all other parties.As a whole, the nation has a two-party system, with the main parties since the mid-19th century being Democratic Party and the Republican Party. However, some states and cities have been dominated by one of these parties for up to several decades. Generally, the Democratic Party dominate in the urban metropolitan areas, while the Republican Party dominate in the rural areas. Following the 2018 elections, the Republican Party continued to hold a majority of State Legislatures and a majority of Governorships. However the Democratic Party won a majority of seats in the House of Representatives, while the Republican Party increased their majority in the the Senate, resulting in a split Congress. As a consequence of Donald Trump's victory in the 2016 elections, the Republican Party also controls the Presidency.