Intra-Party Divisions and the Electoral Success of Party Policy Shifts

To sustain substantive representation, parties need to shift policy positions to align with the evolving preferences of citizens. Spatial theories of party competition predict that voters reward these responsive shifts, but the empirical evidence is mixed. I argue that intra-party dynamics can help explain the lack of observed responsiveness reward. To shift successfully, parties need to make clear and credible long-term commitments, while projecting policy competence. As complex organizations where different actors disagree over key policies, parties frequently face internal backlashes that make this an impossibility. I test the theory with a preregistered survey experiment conducted on a representative sample of the German population (N = 2,400). I find strong evidence that voters reward responsive policy shifts under party unity. Preliminary results suggest that public intra-party contestation reduces this reward by over 50%. Contestation by the party base is punished as much as contestation by intra-party elites. The findings have important implications for our understanding of party competition and democratic representation. They demonstrate that intra-party divisions can meaningfully shape voting behavior and sever the electoral connection between voter preferences and party positions.