This chapter introduces the dynamic partisan perspective on procedural change. Leaders are expected to prefer creating mega-seats in the cabinet (and centralize agenda control), whereas followers prefer (powerful) legislative committees under decentralized agenda control. Leaders’ and followers’ procedural preferences are operationalized by means of the framing of their respective reform proposals. Leaders are expected to emphasize a majoritarian vision of legislative democracy, while followers espouse a proportional vision. All else being equal, followers enjoy a better bargaining position because the proportional vision is more in line with the legislative state of nature. Therefore, the procedural path chosen hypothetically depends on the occurrence of anti-system obstruction which alters followers’ preferences. The chapter closes by discussing the temporal, substantial, and spatial boundaries of the cases selected here. Accordingly, failed and successful procedural reforms in four Western European countries (Britian, France, Sweden, and Germany) will be analysed over the 1866–2015 period.