Collaboration between interest groups and parties often plays a key role in democratic governance and shapes both the character of public policy and the quality of democracy. Rather than being directly in touch with the voters, many parties rely on collaboration with interest groups when determining public policy.

A common factor considered is whether interest groups focus on lobbying parties that are their ideological friends or direct their attention toward powerful parties. Many of the historical ties between groups and parties have been of an ideological nature. Prominent examples includes links between socialist parties and trade unions and right-wing parties and business groups. However, interest groups may also decide to focus on pivotal parties, i.e. those parties whose vote can make or break the majority. Such “powerful” parties include centrist parties who are more likely to have the determining vote than extreme parties. They may also include “larger parties” who are also more relevant for coalition building than smaller parties.

What determines the parties that interest groups collaborate with?

Our recent study in Party Politics shows that the extent to which power and ideology affect collaboration between individual parties and interest groups depends on the institutional context in which the two interact. In some political systems, ideology is more likely to act as a driver for collaboration than in others. Similarly, the tendency to lobby powerful parties may not be equally strong in all systems. Our analysis is based on survey responses from more than 750 Danish and Dutch interest groups about their degree of collaboration with the different parliamentary parties.

We argue that patterns of cabinet formation (wholesale or partial alteration) influence the emphasis groups place on collaborating with ideologically aligned versus powerful parties. Extending Peter Mair’s work on the structure of party competition, we analyse whether multiparty systems experience different patterns of party-group collaboration depending on whether cabinet formation tends to be wholesale or partial. In the former, left and right-wing governments alternate and party competition is bipolar. In the latter, there is partial alteration and the key distinction is between core and marginal parties. These party system dynamics have implications for not only the interaction of the parties themselves, but also their exchanges with interest groups.

Our design compares the Netherlands and Denmark and predicts the degree of collaboration for every interest group-party dyad. The countries are very similar in many respects: both are corporatist systems, have a multiparty system with strikingly similar parties and parliamentary systems with coalition governments. However, they differ in one crucial respect: the pattern of government formation. In Denmark, there has been a tendency for two kinds of governments to exist, either one focused on the social-democrats or one centred around liberals and conservatives.

Political parties are organised in two blocks: one of left-wing parties organised around the social-democrats and one of right-wing parties where the liberals and the conservatives form the axis. In this way, the major cabinet parties in Denmark have traditionally been from either the left or the right, and government changes have been ‘wholesale’. In the Netherlands, cabinets have instead been formed around coalitions of two of the three core parties: the Liberal Party, the Labour Party and the largest Christian-Democratic party. In Denmark you can often predict the government formation as soon as the election result is announced: either the left or the right has a majority. In the Netherlands any kind of government is possible and government alteration has only been partial.

We find similarities in the factors determining party-group collaboration in both Denmark and the Netherlands: groups are more likely to interact with large parties and parties close to the political centre in both countries. However, our study indicates that the relative importance of power and ideology for party-group collaboration is conditioned by the institutional context in which such collaboration occurs. The difference in cabinet formation, we argue, matters for the extent to which power and ideology matter.

In line with our predictions, we show that power considerations (size and extremism) matter less for an interest group’s degree of collaboration with parties in Denmark with a tradition of wholesale cabinet alteration than in Denmark where partial alteration is the norm. In the Netherlands there is more insecurity about cabinet formation therefore interest groups foster strong relations with all three large core parties.

Instead, the tendency for Dutch groups to collaborate with ideologically aligned parties is weaker than in Denmark, where groups operate in a system in which coalitions alternate between the left and the right. There are no significant differences in how frequently Dutch groups – such as business groups or environmental, labour and humanitarian groups – cooperate with the Dutch right and left-wing parties respectively. In Denmark, by contrast, we find that interest groups are divided between those oriented at the right-wing bloc and those oriented at the left-wing bloc. Here, business groups focus more on the right-wing parties, and labour, environmental and humanitarian groups focus more on the left-wing parties. The ideological division that divides the parties in Denmark is more likely to cut through the field of interest groups.

Hence, even if both power and ideology matter for interest groups lobbying in both systems, the extent to which these two factors matter is dependent on the political context. In this way, system-level differences do not only result in overall differences in patterns of party-group behaviour between countries but also shape the rationale underlying the state-of-play between parties and groups within them. This calls for studies which do not examine the direct impact of system-level characteristics on interest group-party relations, but also consider the conditioning impact such system characteristics may have on other explanatory factors.

Note: This article gives the views of the author, and not the position of Democratic Audit UK, nor of the London School of Economics. It originally appeared on EUROPP – European Politics and Policy. Please read our comments policy before commenting.

Anne Rasmussen is a Professor with special responsibilities at the Department of Political Science, University of Copenhagen. In addition, she is affiliated to the Department of Public Administration, Leiden University and a Fellow at the Montesquieu Institute.


Simon Otjes is a Researcher at the Documentation Centre Dutch Political Parties of Groningen University. He has published in the American Journal of Political Science, Party Politics and Electoral Studies. His research has examined political parties, party systems and spatial models of party positions in the Netherlands and the European Union.