 Political sociologists Seymour Martin Lipset and Stein Rokkan (1967) for example used the term in their often cited essay on cleavage structures in West European politics.In their essay, the authors argue how the European party systems at their time of writing were still largely based on the social and cultural cleavages that characterized European societies a century earlier.They therefore argue that these 'frozen party systems' can be seen as political expressions of historically determined societal divisions.