The 2005 Prime Ministerial Primaries held by the coalition of the centre left were less important for their immediate outcome than they were important as crucial events for the institutionalization of primaries in the process of building the Democratic Party. Those held in 2012 were a second step in the same process. Since the two elections differed significantly and were both ‘exceptional’, we first propose a rational narrative of the political strategies leading up to each of them and of the political dynamics that followed. We also analyse indicators of the level of public interest in such a competition and the candidates’ abilities to mobilize support beyond the party’s traditional electoral constituency. Our central argument is that, since the centre-left Prime Ministerial Primaries achieved the strategic goals of some of their proponents, this particular type of primary should be less frequent in the future, at least on the left of the political spectrum. Even though they did so in very different ways, they both strengthened the project of creating the Democratic Party as an ‘open party’, whose leader is chosen by a broad base of electors in a primary-like competition and is the party’s natural candidate for the premiership (view the full paper).