The purpose of this essay is to analyse the Christian democrats and the Sweden democrats’ ideological changes regarding their law and order and migration policies based on their election manifests from 2002-2018. The aim is then to explain these changes with the help of Downs (1957) based on cooperation, ideological superiority, and internal party changes. The question is whether the political parties have become ideologically and politically similar and if Downs (1957) theory will be able to explain this. The chosen method for the study is a theory testing case-study with an ideological analysis compared over time. The political parties’ ideological changes are shown in a descriptive analysis upon which Downs (1957) theory is applied. The study’s conclusion is that the theory can be used to explain the political parties ideological and political convergence. However, it cannot conclude which aspect that has been the most significant to explain the ideological changes that have occurred.