We investigate the role of party group coordinators on committees in the European Parliament. Tying in with previous work on committee and rapporteurship assignment, we focus on key party political actors in legislative politics. Party group coordinators are the nexus mediating between individual MEPs, national party delegations that citizens voted for, and the European party group. They assign rapporteurships and compile voting instructions along which MEPs vote very cohesively. Against this backdrop, and in line with partisan theory, we expect the party leadership to closely monitor their performance. Drawing on a novel dataset comprising information on coordinators in the four biggest political groups in EP6 (2004-2009) and EP7 (2009-2014), we provide evidence that coordinators are indeed representatives of the leadership and that more disloyal coordinators are replaced. Since coordinators are essential checks on rapporteurs and shadow rapporteurs, these findings alleviate concerns about possible agency drift in trilogues and committee specialisation in general
