Party system

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A party system is a concept in comparative political science concerning the system of government by political parties in a democratic country. The idea is that political parties have basic similarities: they control the government, have a stable base of mass popular support, and create internal mechanisms for controlling funding, information and nominations. The party system concept was originated by European scholars studying the United States, especially James Bryce, Giovanni Sartori and Moisey Ostrogorsky, and has been expanded to cover other democracies. Party systems can be distinguished by the degree of political fragmentation, proportionality of seats-to-votes ratio and barriers to entry to the political competition. Main classification of party systems is using the number of parties. Counting the "effective number" of parties is somewhat tricky since the decisions need to be made as to which parties shall be included into the count. Including all parties usually makes little sense: for example, in the 2005 United Kingdom general election 16 entities run candidates and 12 got seats in the parliament, however, no researcher would argue that UK at the time had a 16- or 12-party system. The practical choice would be between a two-party (Labour won 35% of the vote, Conservatives 32%), or three-party system (Liberal Democrats got 22%). Some researchers suggest to exclude parties with low percentage of votes (for example, Alan Ware recommends a 3% threshold), others, like Giovanni Sartori, suggest looking at the history of participation in the governments. The 2005 UK example will yield 3 parties if Ware's definition is used and 2 parties if Sartori's definition is chosen, since the Liberal Democrats almost never influenced the government formation.