In the Swedish 2010 national election campaign one of the slogans presented by the Liberal Party was “Yes to Europe”. 2 The party’s idea was probably not to wish for Sweden to become like the rest of Europe in terms of having a populist right party in parliament, but that is what happened. After the election in 2002, when the populist/nationalist party Sweden Democrats gained representation in many municipalities, opinion polls had shown an increasing support for the party; and in the election of 2010, the Sweden Democrats entered the Swedish parliament, the Riksdag, for the first time, with 5.7 per cent of the votes. 3 With the election of 2010 it was proved that the Swedish voters, at last, were willing to give a party with a populist xenophobic and/or nationalist political programme type a place in the highest legislative institution in Sweden, the Riksdag. As in most other European countries, support for the Sweden Democrats is comparatively strong from the working class—a phenomenon that might be seen as something of a paradox. Sweden has for many years been known as a society with solid class voting, a uni-polar ideological conflict pattern organized around economic left and right, a non-polarized political climate and also a social democracy tightly connected to the welfare state. The conditions were therefore not the most favourable for an anti-establishment, populist or right-wing party to make a sizable footprint in the Swedish working class. Nevertheless, it happened. This chapter is an attempt to explain how this could be understood. The explanation is framed in a discussion of previous research on social cleavages and political alignments, and more specifically of the importance of incorporating both the citizens’ side (demand) and the party side (support). After a presentation of the general theoretical framework we proceed with a discussion of the decreasing class voting in Sweden as well as the decreasing left–right polarization between the main parties in the Swedish party system. In light of this opportunity structure we employ an individual-level regression analysis, decomposing the correlation between working-class position and sympathy for the Sweden Democrats into class-related factors, taking into account attitudes to politics as well as position along economic left–right and authoritarian–libertarian ideological dimensions.