A party system is the environment and structure that parties exist in. There are different relationships between political parties in different countries. This is based on several factors including the political culture of that country and the way that the government is designed in the constitution.
The party system reflects the pattern of relationships between individual parties in relation to each other. The composition of a party system results mainly from two factors. On the one hand it is the structure of social conflicts and interests. Classical conflicts are for instance those between capital and labour or those between secular and religiously oriented parties. On the other hand, the party and electoral laws also influence the party system. These laws can affect how easy or difficult it is to create new parties and if the electoral system allows for larger number of parties in the parliament or not.
The system of government also influences the party system. Parliamentary system offers more influence for political parties because the government emerges directly from the parliament, which is dominated by the parties. In a presidential system, it is the head of government—the president—who is directly elected by the people and thus its legitimacy is based not primarily on the parliament.
The number of parties represented in parliament is only slightly influenced by the system of government. This is rather a question of social cleavages, eventually also the ethnic and other cleavages in a country, the structure of conflicts and interests and the electoral system.
Party systems are most frequently classified according to the number of parties that are seeking power. In this way, one can differentiate one, two and multi- party systems. In a “single-party” system only one party dominates and there is practically no political competition between parties. “Two-party system” means that two parties primarily dominate the political competition, while other, smaller parties only play a subordinate role. In a “multi-party system”, more than two parties have an effect on the political competition (Hofmeister and Grabow 2011: 18).
Dominant-party Systems
In a dominant-party system, one party is so popular (or powerful) that it is the only party with a good chance of winning elections. This system is common in countries that got their independence from a colonial power after a liberation struggle. In this case, the political or military organisation that won the conflict often becomes the ruling party of the country for many years. This is often because of the legitimacy it got from leading the country to independence and/or the power it gained during the struggle.
Examples include ZANU-PF in Zimbabwe (in power since independence in 1980), or the African National Congress of South Africa (in power since the end of Apartheid in 1994). A more extreme version of this is the “single-party state”, where there is only one party and forming other parties is against the law. Examples of this system include the authoritarian regimes in China and North Korea.
Two-party Systems
Two-party systems are dominated by two major political parties. Other smaller parties exist, but only two parties are able to get enough votes to win an election.
These parties are usually popular enough that they can win enough votes to have a majority in the legislature. In this system, power usually changes between the parties every two or three elections. Two-party systems are usually very competitive because what is bad for one party is good for the other. This leads to a situation where cooperation in government can be difficult. Two-party systems are more common in single member district electoral systems. Examples of this kind of system include the UK, France and the USA.
Multiparty Systems
A multiparty system is when more than two parties have a good chance of coming to power, either on their own or by joining with other parties in a “coalition”. A coalition is when two or more competing political parties join together to increase their chances of winning an election. They usually do this to get enough votes to form a majority in the legislature.
Coalitions can either happen before or after an election (once the votes have been counted and there is no clear winner). In this system, the government is often made when several parties come together to make a coalition government. In a coalition government, the different parties share the responsibilities of running the state. For example, the Minister of Education will come from one party and the Minster for Health will come from another. Coalition members formulate a policy agenda (based on negotiation) that indicates what they want to implement/realise during their term. Multiparty systems are more common in proportional representation electoral systems, such as those used in Brazil, Finland and the Netherlands.
Coalition building is an important feature of multi-party politics, especially in countries where parties cannot gain an absolute majority in parliament. In that case, two or more parties will always have to reach an agreement about what policies to implement and whom to appoint as ministers. But in addition to that, parties have to find support in society, for instance by collaborating with special interest groups and non-profit organizations (McLaughlin 2013: 152-153).