Political or Financial Benefits? Ideology, Tenure, and Parliamentarians' Choice of Interest Group Ties

This article develops and tests a parliamentarian‐centred decision model of the collaboration between interest groups (IGs) and parliamentarians. We posit that parliamentarians face a trade‐off when deciding on IG ties that offer them either political (policy support and votes) or financial benefits (additional income). We theorise the balance in this trade‐off to be moderated by ideology and tenure because both introduce variations in IG ties' utility across politicians. Using Swiss longitudinal data from 1985 to 2015 on 743 parliamentarians and their 5,431 IG board positions, we show that parliamentarians become more financial benefit‐seeking over time. This holds in particular if they belong to right‐leaning parties. We also find self‐imposed restrictions for new and left‐leaning parliamentarians on seeking financial benefits. This highlights that parliamentarians are responsive to their partisan constituents when building their IG tie portfolio.