Abstract. Studies of party politics and party competition in West European democracies all point to diversification. Non-economic issues such as the environment, refugees and immigrants or law and order have become increasingly central to party politics. However, there has been surprisingly little interest in explaining variation across time and countries concerning which issues actually become central to party competition. From the sparse literature, two general answers can be discerned. One is societal, focusing on mass media coverage, public opinion and the development of the policy problems related to the issue. The other focuses on the structure of party competition itself – more precisely on the incentives for different parties in drawing attention to different issues. This study stresses the importance of the latter based on a study of the immigration issue in Denmark and Sweden. Party political attention to this issue in the 1990s has been considerably stronger in Denmark than in Sweden. This can be explained by the different strategic situation of the main stream right-wing parties in the two countries. Focusing on the immigrant issue easily leads to a conflict with the centre-right, especially social liberal parties. In Sweden, such a conflict would undermine mainstream right-wing attempts at winning government power. In Denmark, the Social Liberals governed with the Social Democrats in the 1990s, which made it attractive for the main stream right-wing parties to focus on the issue in order to win government power based on the support of radical right-wing parties.