In this special issue of Statsvetenskaplig tidskrift, six articles have, based on hypotheses about cartelization, studied changes in the party groups of the Swedish Riksdag: Are parliamentary party groups becoming increasingly similar from the late 1980s to the early 2010s? When this concluding article summarizes the results from each of the six studies, the simplified answer is no. The relationship between cause and effect, stipulated by the cartel theory, did not occur in our study. Still, public party finance and, to some extent, medialization paved the way for cartelization, and the internal party culture, in this investigation, changed so it could facilitate cartelization. Nevertheless, the increased degree of politicization, did not support the theory of the cartel party, nor did important gender cleavages.