The role of digital media practices in reshaping political parties and election campaigns is driven by a tension between control and interactivity, but the overall outcome for the party organizational form is highly uncertain. Recent evidence contradicts scholarship on the so-called "death" of parties and suggests instead that parties may be going through a long-term process of adaptation to postmaterial political culture. We sketch out a conceptual approach for understanding this process, which we argue is being shaped by interactions between the organizations, norms, and rules of electoral politics; postmaterial attitudes toward political engagement; and the affordances and uses of digital media. Digital media foster cultures of organizational experimentation and a party-as-movement mentality that enable many to reject norms of hierarchical discipline and habitual partisan loyalty. This context readily accommodates populist appeals and angry protest—on the right as well as the left. Substantial publics now see election campaigns as another opportunity for personalized and contentious political expression. As a result, we hypothesize that parties are being renewed from the outside in, as digitally enabled citizens breathe new life into an old form by partly remaking it in their own participatory image. Particularly on the left, the overall outcome might prove more positive for democratic engagement and the decentralization of political power than many have assumed.