Abstract Political parties are increasingly adopting more inclusive candidate selection methods by introducing primary elections. This paper identi es motives of this change, as well as decision makers leading to this introduction. We view a party as a coalition of factions, composed by a party elite and a dissenting faction. By developing a game- theoretical model of interplay between the party elite and the dissenting faction, we fi nd that the primaries are introduced in two scenarios: (1) when the party elite fi nd itself in a weak position under the credible threat of the dissidents to leave the party and (2) when there is a high cohesion between both factions and the party elite itself takes the initiative in introducing primaries. Keywords: Political parties, Primaries, Party split, Party factions, Candidate selection, intra-party politics. JEL Classi fication Number: D71, D72