Competition between unequals: The role of mainstream party strategy in rising party success in Western Europe

Over the last thirty years, Western European political systems have been characterized by instability and change. However, despite an increase in voter volatility and the number of new parties infiltrating the political arena, the same mainstream parties have remained dominant since the late 1960s. Recognizing the electoral and ideological threats posed by new political challengers in an era of partisan dealignment, how do we account for this stability in the face of such change?;While most theories have emphasized institutional or sociological factors, they have overlooked the importance of established parties' strategies in determining the competitiveness of the political space and the electoral fortunes of rising parties. My dissertation addresses this lacuna by developing a model of party strategic interaction which predicts both the tactical choices of the mainstream parties and their success in undermining the electoral strength of these new parties.;Mainstream parties have been able to manipulate the attractiveness of themselves and others by altering, not only their programmatic positions, but also the salience and ownership of those new issues for political competition. Consequently, spatial proximity is no longer necessary for a strategy to be effective; parties from across the political spectrum respond to and can affect---worsen or improve---the electoral fortunes of the rising party. While the interaction of established parties' strategies have caused the decline of most rising parties, that outcome is not a given. First, timing is crucial; mainstream party hesitation means rising party success. Second, while threatened parties use strategies to undermine the attractiveness of these neophytes, established parties not directly threatened by the new actors have the ability to use rising parties as weapons against other mainstream actors. Therefore, for the effects it has on inter-mainstream party competition, rising party success is often a desired outcome.;Systematic, quantitative comparison of mainstream party-rising party competition across eighteen Western European countries, supplemented with in-depth cases studies of party interaction in Great Britain and France, confirms the centrality of deliberate mainstream party strategies to the electoral weakening and, in a few cases, strengthening of ethnoterritorial, environmental and radical right parties.