Ideological coherence within parties: Portugal and Spain

The topic of ideological coherence within parties has attracted less attention compared to the ideological congruence between parties and voters. In addition, party-related variables have not been addressed sufficiently when explaining variation in the degree of ideological heterogeneity. This chapter contributes to filling these gaps by considering the impact of the candidate selection process and political experience on ideological coherence at the elite level. Based on surveys of MPs conducted in Portugal in 2016 and in Spain in 2018, this study analyses the impact of these variables on ideological coherence. The study has the potential to contribute to a broader comparative literature by examining not only variation across parties and over time but also the importance of informal dynamics. The findings suggest that parties display a higher level of intra-party ideological coherence in Portugal compared to Spain, although party-related variables are not significantly associated to ideological coherence.