Explaining interest group interactions with party group members in the European Parliament: dominant party groups and coalition formation

This article develops and tests a theory of party group lobbying that demonstrates how the European Parliament's decision-making process shapes interest group interactions with legislators. Interest group behaviour is highly conditional on two motivations: lobby powerful MEPs, and lobby friendly MEPs. Friendliness is based on ideology, with power shaped by institutional rules and seat share. These goals can mutually reinforce each other. However, because these two motivations exist, and because political power is not fully predictable, there are strong incentives for interest groups to lobby party groups that are non-natural allies to ensure that their policy information reaches the winning side. But, when interest groups engage in this behaviour, they retain their preference to lobby the friendliest members. The analysis is carried out on nine policy-related categories of interest group, with MEP data from three parliaments in the period 1999–2011, combined with information on the parliamentary role of 724 respondents