Different Party Systems

Test yourself on Different Party Systems

Test your knowledge with free interactive questions on Seneca — used by over 10 million students.

Dominant- and Single-Party Systems

There are five main types of party systems: the dominant-party system, two-party system, single-party system, two-and-a-half party system and multi-party system.

Dominant-party system

A dominant-party system is where only one party has a realistic chance of winning political power even though a number of parties stand in the election.
This could be because of electoral fraud, exploitation of state resources or genuine popularity.
- The African National Congress in South Africa has won every election since 1994, so could be seen as a dominant party.
- In Japan, the Liberal-Democratic Party has been in power almost continually since 1955.

Single-party system

A single-party system (or one-party state) is a system in which only one party exists and all other parties banned.
The single party which dominates has complete control over the election and often exists in political systems in which one person rules.
- The Democratic People’s Republic of Korea (North Korea) operates in a single-party system.
- The Lao People's Revolutionary Party in Laos is the only legal political party.

Two-, Two-and-a-Half, and Multi-Party Systems

There are five main types of party systems: the dominant-party system, two-party system, single-party system, two-and-a-half party system and multi-party system.

Two-party systems

A two-party system is where only two political parties have a chance of success at an election, and so power shifts between those two parties.
The First Past the Post electoral voting system is more likely to result in a two-party system.

Examples of two-party systems

The UK has traditionally been dominated by Conservatives and Labour, although smaller parties have become more significant in recent years.
The United States has a two-party system dominated by Republicans and Democrats.

Two-and-a-half-party systems

Two main parties exist in the party system, but a third, smaller party challenges the dominance of the two main parties.
In the 2010-2015 coalition government, the Liberal Democrats could be argued to be the half-party.
- They didn't achieve enough votes to form a majority but could support the Conservatives in a coalition.

Multi-party systems

A multi-party system is where more than two parties have the possibility of winning an election or of being able to take up a role in power as part of a governing coalition.
The government in a multi-party system will often be a coalition made up of a number of political parties.
A multi-party system often is the result of a proportional representation voting system.

Examples of multi-party systems

Germany is an example of a multi-party system, where coalitions are formed to govern the country.
Following the 2017 federal election, a coalition was formed between the Christian Democratic Union/Christian Social Union and the Social Democratic Party, governing into the late 2010s and early 2020s

What is the UK's Party System?

The UK has traditionally had a two-party system, but the rise of other parties has led to a case being made that the UK is moving closer to that of a multi-party system.

Dominant party system

It could be argued that the UK reflected a dominant-party system under the Conservatives from 1979-1997 and under Labour from 1997-2010.
- However, both periods still involved meaningful opposition and electoral competition.

Two-party system

Only Labour and the Conservatives have a chance of forming a government or being the leading partner within a coalition because of their extensive support.
- They still take a large % of the popular vote in elections.
- Party membership is still the highest.
Minor parties in UK politics have not been able to maintain much popularity and support, and their success rarely lasts.
However, in the 2024 General Election, smaller parties increased their vote share and parliamentary presence.
UKIP’s support has collapsed.
The Green Party has seen modest parliamentary representation since 2010, including gains in the 2024 election.

Two-and-a-half-party system

The 2010-2015 period could be argued to be a two-and-a-half-party system, with the Liberal Democrats the 'half' party.
While the Conservatives had a majority in 2015, they lost it after the 2017 snap election.
The need to rely on a third party to support the government suggests that the UK may have a two-and-a-half-party system.
The Liberal Democrats lost 49 seats in the 2015 general election, significantly reducing their parliamentary presence, though they have since partially recovered some influence.

Multiparty system

There has been support at general elections for minority parties in recent years and a number of parties are seen as important political players.
In devolved elections, minority parties have had significant success under electoral systems such as proportional representation.
- Other voting systems (such as Alternative Vote) can help elect parties with a more thinly spread support.
Following the 2024 general election, the UK political system shows greater fragmentation than in previous decades.

2024 general election update

The Labour Party won a clear majority government, meaning no coalition was required.
The Conservatives remained the main opposition, but with a significantly reduced position.
The UK still shows two-party dominance (Labour vs Conservatives).
However, there is increasing support for minor parties.
- Parties such as the Liberal Democrats, Reform UK, Green Party, and SNP continue to influence politics.
The system is becoming less purely two-party and more competitive.