Party system

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.