The rise of Matteo Renzi is one of the most significant political events of the year. This chapter analyzes Renzi's leadership of the Partito Democratico (PD), looking at both the internal politics of the party and the party's position within the Italian party system. Within the PD itself, Renzi has brought take-it-or-leave-it proposals to the party executive, which has upset a vocal minority. More broadly, Renzi has moved the party to the center on the left-right scale, while adopting a more expansionary fiscal stance, effectively marginalizing other parties. The chapter concludes that the most serious opposition to Renzi today may come from within his own party.