ABSTRACT
This account begins with a simple definition: party system change occurs when the defining properties of that system are transformed. In other words, a party system changes when that which is transformed is of systemic relevance, thus necessitating a re-classification of that system. It follows from this that party system change, unlike party change per se, is a relatively rare phenomenon. Notwithstanding the possibility that the electorate may be in a more or less continuous state of flux, or that the social forces around which the parties are grouped may shift and settle in regular cycles of dealignment and realignment, or that individual parties may come and go, it is nevertheless clear that it is only in certain specific circumstances that such changes will also be of systemic relevance and, hence, that party system change can be said to have ocurred.
