The European Parliament's mandate for trilogues: explaining the discretion of political group advisors.

To fully grasp EU inter-institutional negotiations, we need to understand how EU institutions internally prepare for trilogues and what the involvement of staff actors is in this process. This article sets out to uncover the backstage co-ordination of the European Parliament's (EP) mandate for trilogues and seeks to explain the discretion of political group advisors (PGAs) in these preparations. Based on interviews and a survey, it identifies the conditions reinforcing or constraining their autonomy. PGAs' autonomy is highest during the early stages of co-ordination, ahead of group and shadows meetings. PGAs then act without clear instructions and base their actions on what they deem to be in line with the group's political agenda. Trust is a necessary condition for their pro-active involvement in the intra-institutional negotiations, since (shadow) rapporteurs allocate work to EP staff actors only when they can rely on their loyalty. In addition, advisors' political sensitivity and informal networks enable them to accurately represent political positions in negotiations at staff level and formulate strategies acceptable to Members of European Parliament (MEPs). [ABSTRACT FROM AUTHOR]