Immigration has become a ‘hot’ and contested issue in the political agenda of most western democracies, with multiple ramifications for the social cohesion of democratic societies. But, how does it become so? How does the issue of immigration become politicised? Are politicians paying attention to the issue by following or responding to the public opinion in their quest for votes? Or are they leading the public in the absence of prior strong positions about it to create a new niche of voters? In addition to addressing these questions in relation to the responsive (or otherwise) nature of politicians’ agenda-setting, this paper will also examine the changing dynamics of issue emergence. There is some discussion as to whether the competitive dynamics around the issue of immigration are better depicted by spatial models (based on the notion of positional issues) or by non-spatial ones (linked to valence issues). We will argue that the emergence of the immigration issue indicates that parties shift between both types of dynamics of party competition around this issue. The lack of chrystallisation of the issue in the electoral arena at an early stage of its politicisation means that some times parties take clear polar positions on the issue, while other times they refrain from taking sides and play the competence card on it. The paper addresses these questions by analysing time series since the mid-1990s of public opinion surveys in Spain, as well as the electoral party manifestos, media appearances and parliamentary activity of the main parties represented in the Spanish parliament (data collected by the SOM and SPAP projects).
