Interest Group Influence on Political Parties in Western Democracies

Abstract: This thesis asks when and why interest groups influence political parties. I address this question in two ways: 1) by examining the organizational ties between parties and interest groups, given that party-interest group ties may constitute an important step on groups' way to influence, and 2) by more directly examining interest group influence on parties. By doing this, the thesis contributes to the literatures on interest group influence, party positions, and party-interest group ties. Paper I examines the relationship between private and public party finance and party-interest group organizational ties. The paper lends systematic support to the idea that groups and parties are more likely to maintain closer relationships today when the groups donate money. The institutional setting the actors operate in may furthermore affect ties.Paper II gives an overview of the Party-Interest Group Relationships in Contemporary Democracies (PAIRDEM) datasets, and presents descriptive results regarding the organizational ties parties and interest groups maintain today. Paper III considers the relationship between parties' goals and interest group influence on parties. I find that interest groups are more likely to perceive that they influence parties they are ideologically similar to as well as parties that are more willing to compromise on policy. Interest groups' access to parties moreover seems to be an important mechanism here. Paper IV asks whether organizational ties affect one-sided interest group influence on parties as well as mutual party-interest group influence. We find positive correlations between stronger ties and both types of influence.Paper V asks when parties listen to interest groups and adopt their input. I find that parties are more likely to do this when 1) the issue in question is less publicly salient, 2) parties emphasize the issue more than their competitors, 3) the interest group input is supported by a larger and/or more coordinated interest group coalition, and 4) parties are in opposition.