It is often assumed that political parties have more fluid party platforms than in the past because internal veto players – like party activists – have lost the power to restrain the office-seeking party elite. Several case studies subscribe to this view. However, there is no systematic assessment of this relationship. Using new data this research note investigates this relationship and finds a clear positive effect of leadership domination on party platform change. With leadership domination increasing over time, our model predicts increasing fluidity in party platforms. This note provides a motivational and a numerical argument in favor of this hypothesis, considers alternative hypotheses and provides empirical evidence for the claim using two different datasets.