Perhaps most important characteristic of modem western European party systems has been their long-term stability in face of widespread and deep-seated social change. While many countries have seen accelerating changes in social stratification, social mobility, and urbanization in postwar years, their party systems have been, with minor exceptions, largely immune from repercussions of these changes.' Political sociology has produced two different emphases to account for this political ossification. On one hand, Seymour Martin Lipset and Stein Rokkan have argued that, while party systems and cleavage structures result from complex interaction between fundamental social cleavages (mainly class, religion, and region) and patterns of institutional development, once translated into political divisions they acquire a momentum which permits them autonomy from potentially destabilizing social change.2 On other hand, Giovanni Sartori has suggested that this approach ignores extent to which various social factors are picked out by elite decision, thereby ensuring continuing adaptability of parties to change in their social bases.3 The Lipset and Rokkan model provided inspiration for first attempts to place Irish politics in a comparative perspective, with varying success. As Ireland appeared to lack class, religious, and regional social cleavages of normal western European countries, John Whyte emphasized the low degree to which Irish electoral behavior is structured at 'all. To explain this he retreated into history: Irish parties are sui generis because the context from which they spring is sui generis also.4 However, by exploring this context, Tom Garvin has demonstrated partial validity of Lipset and Rokkan model by showing that a center-periphery cleavage helped to explain salient division in Irish politics between two major parties, Fianna Fail and Fine Gael, ostensibly based on positions taken in Irish Civil War of 1921 to 1923: Under Celtic imagery, Ireland exhibits an example of a very common western pattern.s5 Irish voters were thus mobilized into United Kingdom polity in nineteenth century before they were proletarianized. Garvin fits dominance of national question in Irish politics into familiar mobilization/state formation/industrialization paradigm.6 The regional and socio-cultural underpinnings of Civil War split have also often been commented on, as has their gradual erosion since then.7 More recently, R. K. Carty has seen Irish case as a theoretical challenge to whole Lipset and Rokkan model. Following Sartori's emphasis on elite management, he stresses creation of a political cleavage around Civil War split