Voting Behaviour in Parliamentary Free Votes: How Party Loyalty Matters

The literature on parliamentary voting behaviour when morality policy issues are on the floor has unearthed an intriguing question: Why do members of parliament (MPs) still predominantly vote with the majority of their party even though the whip is explicitly suspended? According to existing studies, party loyalty, i.e. a feeling of allegiance not related to policy agreement or disciplinary pressures, is an important part of the explanation. Nevertheless, how this loyalty effect might differ among MPs has remained underexposed yet. In our paper, we employ a more nuanced view on party loyalty in ‘free votes’ and argue that identification with their party is not equal among all MPs but likely to be a matter of degree originating from differently effective socialization processes into party structures. We hypothesize that the more strongly an MP’s identification with his/her party, the (1) lower the probability that he/she votes against the majority of his/her party, (2) the weaker the effect of personal and constituency characteristics, but (3) the stronger the effect of party affiliation on the direction of his/her voting decision. We test those propositions quantitatively using a dataset with different measures of MPs’ party socialization and other MP and constituency characteristics in selected ‘free votes’ in the German Bundestag (2009-2017). Our work has important implications for research on legislative behaviour and representation since it offers explanations for the observation that MPs vote with their party even when they do not have to.