A political party is a political organization subscribing to a certain ideology or formed around special issues. In party-list proportional representation, parties (and sometimes multi-party cartels) can play a functional role in the voting system.
In single-party states, only one political party is legally allowed to hold effective power. Although minor parties may sometimes be allowed, they are legally required to accept the leadership of the dominant party. This party may not always be, however, identical to the government, although sometimes positions within the party may be in fact more important than positions within the government.
In one party dominant states, opposition parties are allowed, but are widely considered to have no real chance of gaining power. Often, the dominant party will remain in power by using patronage and sometimes by voting fraud. Examples of one party dominant states include the Liberal Democratic Party in Japan, the People's Action Party in Singapore. Also, one party dominant systems existed in Mexico with the Institutional Revolutionary Party until the 1990's, and in the southern United States with the United States Democratic Party from the 1800's until the 1970's.
Two-party systems are states, such as the United States, in which there are two dominant political parties, with extreme difficulty for anybody to achieve electoral success under the banner of any other party. The relationship between the voting system used and the two-party system was described by Maurice Duverger and is known as Duverger's Law.
Multi-party systems are systems in which there are multiple parties. In many cases, no one party has a chance of gaining power, and parties must work with each other to form coalition governments.
There are notable exceptions and variations:
Single-party, two-party, and multi-party governments
Parties and directions
Political parties are often considered on a political spectrum. One typical spectrum has the Left associated with radical or progressive policies and the Right with conservative or reactionary policies. Other analyses include other dimensions such as the political parties' acceptance of parliamentary democracy as opposed to authoritarian or totalitarian attitudes, and economic policies, the Left favoring social-democracy, socialism or communism, while the Right tends to favor laissez-faire economics.Colors and emblems for parties
Generally speaking, over the world, political parties associate themselves with colors, primarily for identification, especially for voter recognition during elections. Red usually signifies leftist, communist or socialist parties; pink sometimes signifies socialist. Conservative and Christian democratic parties generally use blue. Yellow is often used for liberalism. Green is the color for green parties and Islamic parties.
Color associations are useful for mnemonics when voter illiteracy is significant. Another use case is when it is not desirable to make rigorous links to parties, particularly when coalitions and alliances are formed between political parties and other organizations, for example: Red Tory, "Purple" (Red-Blue) alliances, Red-Green Alliances, Blue-Green Alliances, Pan-green coalitions, and Pan-blue coalitions.
The emblem of Socialist Parties is often a red rose held in a fist.
International organizations of political parties
During the 20th century, many national political parties organized themselves into international organizations along similar policy lines. Notable examples are the International Workingmen's Association, the Socialist International (both red), the Liberal International (yellow), the International Democrat Union (blue), and the Worldwide green parties (green). The Socialist International, the Liberal International, and the International Democrat Union are all based in London.
