National political parties are situated in a multilayered context involving several policy levels, from the local to the international, pointing to the need for scholars to consider parties’ vertical organization strategies (Detterbeck Reference Detterbeck2012). The European level in particular offers national parties in EU member states a wide array of possibilities to be politically active and weigh on European decision-making, but also to gain European insights that may be of use for their domestic decision-making. The European Parliament (EP), for instance, is a straightforward scene where parties can influence policies via their Members of the European Parliament (MEPs). But international activity also takes place through political parties at the European level – Europarties – serving as umbrellas above national political parties from a similar ideological line (Pittoors Reference Pittoors2024).
Facing the complexity of multilevel polities, how do political parties organize? Do they prioritize the national level or the European level? Do they act on the European stage through European institutions and/or through the Europarties? To what extent do national parties want to exert control over what takes place on the European stage? What purpose do cross-level contacts serve? Are national parties even interested in knowing what is going on at the European level? Among the multiplicity of largely unanswered questions on this matter, this research focuses on understanding how competing (though not mutually exclusive) logics of political behaviour interact within political parties, observed from a national rather than European perspective, aiming to explain their multilevel organization.
To grasp the complexity of the cross-level linkages of national parties, this article builds on the clear-cut typology developed by Gilles Pittoors (Reference Pittoors2023). The typology outlines four kinds of cross-level party organizations (integrated, federated, consolidated or separated) and identifies different strategic foci for each of these types. Going beyond identifying types, this article wants to understand why certain parties fall within a particular type. To do so, we conduct a Qualitative Comparative Analysis (QCA) of 19 national political parties from three rather similar European countries: Belgium, Denmark and the Netherlands. For our analysis, we deliberately rely on party-level factors rather than the much-used contextual factors at the country level, such as EU politicization (for instance, see Pittoors and Gheyle Reference Pittoors and Gheyle2024), or at the European level, like the degree of institutionalization of Europarties. We contend that, in order to explain multilevel party organization, we should focus on the very characteristics of the parties whose organizational strategies we strive to understand, and not remain at the upper country or European levels, blind to variations at the level of individual parties.
Concretely, we consider five key conditions that will help identify parties’ causal paths towards a particular multilevel organization strategy. At the party level, we consider whether a party belongs to a mainstream party family, is centralized, is in government and whether it has an outspoken opinion on the EU. Additionally, at the individual level we also consider the seniority of their MEPs. To determine parties’ values on each of these conditions, we anchor our research deeply in the empirical reality of each party under study. In addition to making extensive use of the Chapel Hill Expert Survey (Bakker et al. Reference Bakker, Hooghe and Jolly2020), we conducted 68 semi-structured interviews with party elites at both the European and national levels, and we analysed national party statutes to account for formalized rules. This rich empirical strategy allows us to have an accurate understanding of each party and the context in which it operates, thereby enabling us to interpret the results of the QCA in a reliable way.
Our study confirms our initial expectation that the political party perspective is a useful lens through which to understand the parties’ own organizational dynamics. We show that excluding party- and even individual-level factors leads to missing important parts of the story: past experiences and current dynamics within national political parties, and the individuals that populate them, can help us understand how they apprehend their interactions with the European level. Another key lesson from this research is that one cannot merge all aspects of multilevel politics in the EU into one single factor or refer to a single variable to explain party behaviour across member states. National parties diverge significantly in how they interact with the EU, and it is often a combination and interaction of different factors that explain variations.
Parties in the EU: a conceptual and analytical framework
The relation between national parties and the EU is complex, not least because parties are historically tied up with national political systems, while increasingly faced with a European multilevel system that limits their policy options and requires political attention (Hix and Lord Reference Hix and Lord1997). It should come as no surprise then that scholars have tried to capture and explain this complex relationship from different perspectives. Though several studies have approached this question by looking at the development of parties at the European level (Day Reference Day2013; Johansson and Zervakis Reference Johansson and Zervakis2002; Kosowska-Gąstoł Reference Kosowska-Gąstoł2017), this study explicitly takes the perspective of national parties. A key issue that remains underdeveloped in the literature is variation at the level of individual parties: how and why do parties differ in the way they manage their relations between the national and European levels?
Major contributions have been delivered by the party Europeanization literature, which studied how European integration alters the power structures of national party organizations top-down (Ladrech Reference Ladrech2012; Poguntke et al. Reference Poguntke, Aylott and Carter2007). Yet, despite finding quite some variation, their main conclusion has been that party organizations did not go through any fundamental alterations. Nicholas Aylott et al. (Reference Aylott, Blomgren and Bergman2013) even questioned whether the observed changes were directly linked to European integration. Alternatively, studies focusing on the more bottom-up relationship between national parties and the European level predominantly use a principal–agent perspective to assess how national parties control the voting behaviour of their MEPs and ministers in the European Council (Hix Reference Hix2002; Mühlböck Reference Mühlböck2017; Raunio Reference Raunio2000). Again, however, despite noting some variation, these studies conclude that parties generally invest little in controlling their EU-level agents.
However, while these studies generated important insights on parties’ general resistance to Europeanization, and about the commonly high autonomy of EU-level agents, what we know too little about still is how national parties differ regarding their concrete organizational practices in linking the European and national levels, and the reasons for these divergences. On the one hand, in cases where parties do not fundamentally alter their organization, this does not mean they do not manage their (day-to-day) relations with the European level in a particular way, which might well diverge significantly from the way in which other parties manage their relationships. On the other hand, there is no reason to assume that a struggle over control/autonomy is the only or even main kind of relationship between national parties and the EU level. Not all parties are necessarily interested in controlling EU-bounded actors, instead preferring, for instance, a cross-level information exchange (Pittoors Reference Pittoors2023).
Capturing organizational variation: a holistic approach
This calls for a more holistic approach to national parties’ linkages with the European level, which should be seen as part of a wider multilevel organizational strategy. To develop such an approach, this article turns to comparative federalism. Indeed, the ‘linking of activities and strategies at two different levels’ (Deschouwer Reference Deschouwer, In Katz and Crotty2006: 299) is a key feature of the federal party literature, where it is referred to as the vertical integration of parties (Detterbeck Reference Detterbeck2012). While some conjoin the notions of vertical integration and cross-level autonomy (Verge and Gómez Reference Verge and Gómez2011), it is important to disentangle them. As Lori Thorlakson (Reference Thorlakson2011: 717–718) argues, while autonomy refers to the ‘capacity to act without constraint or interference’, integration is concerned with ‘organisational, cooperative and resource linkages’. Even though both might obviously be related, equating them is neither theoretically necessary (Detterbeck Reference Detterbeck2012: 66) nor empirically supported (Thorlakson Reference Thorlakson2011: 718).
To make this more concrete, we build on the framework developed by Pittoors (Reference Pittoors2023), who argues that vertical integration of parties in the EU context is about the institutionalization of interactive practices between party actors at the national and European levels. Moreover, this research makes a distinction between internal linkages (e.g. between a party’s own MPs and MEPs) and external linkages (e.g. between national party leaders and Europarty leaders), on the basis of which it identifies four different types of multilevel party organization in the EU. An integrated party incorporates systematic cross-level interaction both internally (with ‘its’ MEPs, ministers and Commissioners) and externally (with the Europarty and broader network). By contrast, a separated party is one where these linkages are not institutionalized at all, but ad hoc and temporary. Between these opposites, federated parties put the emphasis rather on the external dimension via transnational linkages, while consolidated parties invest more in strengthening internal coordination. Table 1 gives an overview of the different types and their main characteristics.
Ideal-typical Categories of Parties’ Multilevel Organization
Source: Based on Pittoors (Reference Pittoors2023).
Explaining variation: party goals, genetics and individuals
The literature on party behaviour in multilevel systems is vast and complex (Detterbeck Reference Detterbeck2012; Hough and Jeffery Reference Hough and Jeffery2006), though it often focuses on party systems (Thorlakson Reference Thorlakson, In Hough and Jeffery2006) or relations of control and autonomy between principal and agent across levels (Hix Reference Hix2002; Mühlböck Reference Mühlböck2012). Taking the asymmetry of the European party system as a given (Thorlakson Reference Thorlakson2017), this study further considers that parties can use cross-level linkages for other purposes than mere control over an agent. Some parties might indeed insist on the strict control of their MEPs (and thus aim for ‘consolidation’, to use the typology detailed above), but others might be more interested in exchanging information about EU legislation, while yet others might not want anything to do with Europe at all. Yet, the literature does not elaborate much on why parties might use and organize their cross-level linkages differently.
The Europeanization literature often points at how the domestic political irrelevance of European affairs generates too few incentives ‘for party elites to change’ (Poguntke et al. Reference Poguntke, Aylott and Carter2007: 226). Party leaders often ignored or downplayed the EU due to a lack of public interest, but also internal divisions within parties. This approach kept Europe as a secondary issue, with low importance for voters and little incentive for parties to adapt (Mair Reference Mair2000). Robert Ladrech (Reference Ladrech2012) suggested reintroducing the EU into domestic politics to create electoral consequences, potentially prompting Europeanization. Similarly, Thomas Poguntke et al. (Reference Poguntke, Aylott and Carter2007) theorized that as the EU gains more attention domestically, hurdles to Europeanization may decrease. These arguments suggest that EU politicization could serve as a necessary catalyst for Europeanization, as parties often need an external shock to prompt action (Gauja Reference Gauja2017).
However, recent research has been critical of attributing politicization such a crucial role. For one, Pittoors (Reference Pittoors2024) has shown that differences in politicization between countries alone cannot fully explain party Europeanization and call for a new approach to explaining party Europeanization that includes a wider range of explanatory factors. Not to mention the fact that, despite multiple crises that Europe has faced in recent years, overall politicization remains rather limited (Hutter and Kriesi Reference Hutter and Kriesi2019). Moreover, while Roman Senninger and Daniel Bischof (Reference Senninger and Bischof2017) found significant evidence of cross-level linkages and showed that these are (partly) contingent on the temporary domestic salience of the issue at hand, this does not say much about parties’ institutionalized multilevel organizational linkages beyond short-term spikes in cross-level contacts. As such, while politicization as a contextual element is obviously crucial to understand party behaviour, its explanatory power for parties’ relationship with the European level is limited, nor does it account for variation between parties within the same political system.
Therefore, this research goes beyond contextual factors at the country level and shifts focus to party-level factors. From a political-institutional perspective (Hall and Taylor Reference Hall and Taylor1996), such factors are broadly understood as either strategic calculations (Harmel and Janda Reference Harmel and Janda1994) or cultural and historical frames (Duverger Reference Duverger1954; Johansson and Zervakis Reference Johansson and Zervakis2002; Panebianco Reference Panebianco1988). Different logics apply to each of these approaches. Following a cost–benefit logic of strategic goal-seeking, parties would only invest in connecting with the European level if it helped them gain votes, achieve certain policy outcomes and/or capture office. Conversely, the logic of appropriateness dictates that parties will behave according to their cultural and cognitive frames – for instance, investing in linkages with Europe might appear unseemly for parties who want to leave the EU, while the logic of path dependency stresses the enduring effect of historical trajectories and past organizational choices.
However, such institutional approaches tend to overlook the importance of individuals. As argued by Karl Magnus Johansson and Peter Zervakis (Reference Johansson and Zervakis2002: 13), while parties are ‘institutions with distinct cultural and ideological identities, historical heritages, and collective memories … the preferences and motivations of key persons remain of fundamental importance’. Although its empirical relevance is highly debated within the literature, the personalization trend – that the attention in politics shifts from collective actors to individuals (Karvonen Reference Karvonen2010) – points to the relevance of taking individual politicians into account when studying the strategies of collective actors of which they are a part. Centralized personalization is in particular critical for our study (Balmas et al. Reference Balmas, Rahat and Sheafer2014). It entails that leaders within parties are increasingly powerful actors, at the expense of second-rank party elites. It is thus wise to assume that the characteristics of the politicians active in their party will shape how the national and the European levels of the party organization interact. If big names sit in the European Parliament, it is likely that linkages – and influence – will be stronger than when MEPs have no such track record.
Clearly, then, there is no escaping the fact that there is a ‘myriad of complex factors (both internal and external to the party) that come together’ to determine a party’s organization (Gauja Reference Gauja2017: 6). Therefore, to identify the specific conditions to be used in our QCA, we departed from the literature and refined the set of conditions based on factors that came up during the interviews and case studies. Because of the multitude of possible conditions, we do not formulate concrete hypotheses. We rather build on the broad assumption that, whether driven by institutional logics or individual preferences, cross-level linkages can take very different practical forms and serve various purposes. Instead of focusing on questions such as ‘who controls who?’, this research focuses on the way the linkages between the national and European levels are given shape in practical day-to-day terms, and on the interaction between competing (though not mutually exclusive) logics of political behaviour.
Design, data and method
Because of the nature of its objective, this study follows an abductive research design, which strives to understand findings ‘in their configurative context, rather than attribute causality to isolated independent variables’ (Detterbeck Reference Detterbeck2012: 68). First, developing the work initiated by Pittoors (Reference Pittoors2023), the real-life linkage practices of individual parties were qualitatively reconstructed, and each party was attributed an ideal type based on the typology above. Second, putting our data gathered from interviews and party statutes together with the Chapel Hill Expert Survey (CHES) data, we identified the causal pathways towards each type through QCA, identifying and interpreting key causal mechanisms.
Case selection
In total, 19 Belgian, Danish and Dutch parties are studied (Table 2). Because we are mainly interested in variation at the level of individual parties, we have selected these three countries because they are highly comparable. Indeed, Belgium, Denmark and the Netherlands are similar in many ways: they are relatively small, wealthy, north-western European countries with comparable party systems. Their postwar politics have been dominated by three mainstream parties from the traditional party families (socialist, liberal, Christian/conservative), which over the past decades have become increasingly challenged by parties on the left and right ends of the ideological spectrum. Though there are some differences in their relationship with European integration – Belgium is specifically unique in that Brussels is the political heart of the EU – all three countries are long-term members. Moreover, neither their parties nor citizens consider ‘Europe’ to be a highly salient issue, apart from crisis-induced and highly region-specific peaks (Hutter and Kriesi Reference Hutter and Kriesi2019).
Parties under Study
a Notes:
The DF was selected as a case prior to its transfer from the ECR group to the ID group.
b These parties had a European Commissioner at the time of data gathering.
c These parties were in national government at the time of data gathering.
d sp.a changed its name to Vooruit in March 2021, but data was gathered before, so this study uses the party’s old name.
e European People’s Party.
f Alliance of Liberals and Democrats for Europe.
g Renew Europe.
h Party of European Socialists.
i Socialists and Democrats.
j European Free Alliance.
k European Conservatives and Reformists.
l Green Party.
m Identity and Democracy.
n European Christian Political Movement.
Within each of these polities, five parties were selected. The selection of parties had to balance different constraints and requirements. On the one hand, QCA requires maximal diversity among similar cases (Schneider and Wagemann Reference Schneider and Wagemann2012). This meant that parties that belong to the same broad party family within a single country could not both be selected. For instance, in Denmark both Venstre (Left) and Radikale Venstre (Radical Left), notwithstanding ideological differences, largely fall within the liberal party family. The same goes for the Dutch Volkspartij voor Vrijheid en Democratie (People’s Party for Freedom and Democracy – VVD) and Democraten 66 (Democrats 66 – D-66). At the same time, niche parties who made the EU part of their core business – such as Volt or Denmark’s People’s Movement Against the EU – could also not be included as they would distort comparison. Therefore, for each country, parties from five party families have been selected: one party from each of the three mainstream ideological families, one green and one on the harder right. To assist in the selection, we looked at parties’ membership of five EP groups: the European People’s Party (EPP), the Socialists and Democrats (S&D), the Alliance for Liberals and Democrats for Europe ALDE (now Renew Europe (RE)), the Greens(/European Free Alliance (EFA)) and the European Conservatives and Reformists (ECR). This provides a good diversity on party-level elements such as ideology, size, age or government participation.
It is important, however, to clarify Belgium’s specific case, as its two main regions, Flanders and Wallonia, are nearly completely separated political systems (Caluwaerts and Reuchamps Reference Caluwaerts and Reuchamps2021). In effect, there are almost no ‘Belgian’ parties; only Flemish and French-speaking parties that operate vertically across all governmental levels, though horizontally only in one half of the country, with overlap in the Brussels region (with the noticeable exception of the communist party, which is present all over the country, and not included in this study). Therefore, Flanders and French-speaking Belgium are considered as separate polities, each with their own political dynamics and separate party systems. Accordingly, parties of the same broader families were selected for each of the two regions – though no hard right party is active in the French-speaking part (de Jonge Reference de Jonge2021).
Elite interviews and reconstruction of organizational practices
Aiming to properly capture and interpret the real-life organizational practices of parties in their political context, the study relies on 68 semi-structured interviews with party elites at both the European and national levels, supported by a review of party statutes and respondent validation (see Supplementary Material for an overview of respondents). In addition to people with a bird’s eye view of the party, such as general secretaries, respondents include MEPs, their assistants and staff, as well as national profiles such as MPs with a European portfolio, international/European secretaries and experts on EU affairs. Where available, ministerial advisers were also interviewed, which often have a unique perspective. Because it was agreed that anonymity would be ensured, their names, party affiliations or nationalities cannot be disclosed.
Interviews were conducted both prior to and after the 2019 EP elections (for respectively, Flemish and Dutch parties on the one hand and Danish and Belgian French-speaking parties on the other). Although there is a slight temporal variation in the timing of data collection, this does not affect the comparison as values for the conditions of our QCA analyses have been attributed to each party depending on its own temporal configurative context – considering parties as self-standing cases. During the interviews, several aspects of parties’ organization were gauged. Generally, the interviews explored the linkage arrangements in place, how they work in practice, their effectiveness and purpose. More specifically, respondents were asked about a series of concrete empirical indicators that capture the cross-level interactive dynamics explicated above, focusing on channels and processes of exchange and communication (Table 3). Particular attention was given to the extent to which linkages are institutionalized or take place informally and ad hoc. Moreover, in anticipation of the explanatory analysis, respondents were also asked why their party manages cross-level contacts the way it does (see Supplementary Material for an example interview guide).
Empirical Indicators (Based on Pittoors Reference Pittoors2023)
Importantly, while the categorization of some parties under study has been presented in earlier research (see Pittoors Reference Pittoors2023), the Belgian French-speaking parties are original additions. As such, the interviews and other qualitatively gathered data are used for the reconstruction and ideal-type categorization of these parties’ multilevel organization, but crucially also for the overall interpretation of QCA results and the causal pathways it identifies.
Comparative analysis using QCA
If the qualitative reconstruction of multilevel party organization is descriptive and works towards attributing ideal-typical categories, the QCA is explanatory and aims at determining causal pathways. Best understood as a ‘holistic approach’ (Arel-Bundock Reference Arel-Bundock2019: 2), QCA reduces ‘the enormous complexity that we routinely confront in the social sciences’ (Berg-Schlosser et al. Reference Berg-Schlosser, De Meur, Rihoux, In Rihoux and Ragin2009: 3) by converting cases into configuration – that is, ‘combinations of explanatory “conditions” and subsequent “outcomes”’ (de Vet Reference de Vet2020: 10). Importantly, QCA emphasizes the notion of multiple conjunctural causation: the idea that an outcome can be explained by multiple (combinations of) conditions. As such, the point of QCA is not to assess which factors are most statistically significant, but rather to identify the combinations of conditions that lead to particular outcomes (Haesebrouck Reference Haesebrouck2016).
One should also be aware of the many criticisms made of QCA, particularly regarding the sweeping effect of measurement error in the QCA algorithms (Baumgartner and Thiem Reference Baumgartner and Thiem2017; Collier Reference Collier2014; Hug Reference Hug2013). Vincent Arel-Bundock (Reference Arel-Bundock2019) has coined this the ‘double bind’ of QCA: while measurement error is best prevented by deep knowledge of a small number of case studies, QCA’s algorithms perform best with a higher number of cases. Therefore, this article stresses QCA’s fundamentally qualitative and contextual character. Put differently, this study does not understand QCA and its explanatory formulas as its conclusive results, but instead argues that these still need to be contextualized and interpreted in relation to the rich qualitative data (Collier Reference Collier2014). This justifies the research design employed for this study, combining existing CHES data with rich original qualitative data.
Empirical analysis
This section presents the results of the empirical analysis. We first specify conditions and generate a truth table that will form the basis of the QCA minimization, before presenting the analyses of sufficiency that identify the key causal pathways to each outcome. Importantly, as mentioned earlier, the results of the QCA require further contextualization, and are therefore interpreted in relation to the case studies. A summary of the descriptive findings can be found in the Supplementary Material.
Generating a truth table
A truth table links cases (parties) to configurations of conditions (explanatory factors) and outcomes (organizational types). The outcomes are operationalized categorically into the four mutually exclusive categories identified above (integrated, federated, consolidated or separated multilevel organization). The conditions are operationalized in binary terms, meaning they are either present (value 1) or absent (value 0). We initially approached the analysis with a focus on party-level conditions, which were selected based on arguments in the literature about parties behaving according to strategic calculations and ‘genetics’ (see discussion above).
From a strategic point of view, there are two factors that are of crucial importance for the way parties organize their connections with the European level. On the one hand, government participation – ‘in government’ (1) vs ‘in opposition’ (0) – not only implies a significant informational advantage over opposition parties, but the direct involvement of governing parties in EU decision-making also means they are more explicitly confronted with policymaking responsibilities, while significantly increasing concerns about cross-level cohesion (Carter and Poguntke Reference Carter and Poguntke2010; Poguntke et al. Reference Poguntke, Aylott and Carter2007). As some of our respondents put it: ‘you have to ex officio deal with Europe’, and ‘there is no way to get out of it’ (different respondents). In other words, to be effective as a governing party, one needs to be aware of and involved with European dynamics. Therefore, it is reasonable to assume that being in government would generate a strong directional push towards stronger – that is, more systematic – contacts across levels, when compared to opposition parties who are freer to ignore a traditionally electorally second-order topic (Gattermann et al. Reference Gattermann, de Vreese and van der Brug2021).
On the other hand, strategic investment in cross-level linkages is also likely influenced by parties’ position on the EU. While we acknowledge that the overall politicization of European affairs remains limited (Green-Pedersen Reference Green-Pedersen2019), the degree to which individual parties have outspoken EU positions is likely to affect strategic decisions about whether or not to invest in maintaining contacts with the European level. For instance, a respondent from the Euro-critical SGP said their party expects its MEP ‘to focus on [the European] level without meddling in national politics’, while a respondent from the more Europhile PvdA stated that ‘social-democracy will be international, or it will not be’.
Importantly, we consider that, for effects to show, parties need to have outspoken EU opinions – that is, they need to both have a strong position about the EU and consider it a salient topic. For a party to invest in organizational linkages with Europe, it is not enough for it to be strongly pro- or anti-EU, if it does not also attribute importance to European issues in its programme or campaign. Therefore, to attribute a binary value, we combine the CHES data on ‘EU position’ and ‘EU salience’ (Bakker et al. Reference Bakker, Hooghe and Jolly2020), and give parties with either very high or very low scores on the ends of the spectrum value ‘1ʹ (outspoken), and those in the middle value ‘0ʹ (not outspoken).
From a genetic point of view, the core idea is that parties’ historical (organizational) traditions define their contemporary organization and behaviour (Duverger Reference Duverger1954; Johansson and Zervakis Reference Johansson and Zervakis2002; Koskimaa Reference Koskimaa2020; Panebianco Reference Panebianco1988). We focus on two factors we consider crucial for parties’ multilevel organization. For one, we consider the differences between ‘mainstream’ and other parties. We are aware that the definition of ‘mainstream’ is not always clear-cut (for instance, see Luypaert and Legein Reference Luypaert and Legein2022). To clarify, we use this term to denote those parties that are part of party families that were (re-)established shortly after World War II. We point to the traditional liberal-, social- and Christian-democrat party families, which are entwined with the postwar (re)construction of both national states and European integration. We posit that these three party families have more experience with and traditions of cross-level linkage, likely generating a contemporary directional push towards stronger cross-level linkages for parties belonging to them, even if these parties were not created in the postwar period (e.g. most parties in Central and Eastern European member states). By contrast, niche or challenger parties either do not clearly belong to a party family as such (e.g. regionalist parties), or belong to party families that had less of such formative experience concomitant with European integration (e.g. green parties). Consequently, they had less time, incentives or opportunities to establish and institutionalize cross-level linkages. Parties belonging to a mainstream party family are given the value ‘1ʹ and all others value ‘0ʹ.
Following a similar genetic logic, the degree of centralization within a party is equally important. We consider that in parties where power is concentrated in the hands of the central leadership, what a party does (not) invest in is strongly defined by the national leadership’s focus – which often is not set on second-order Europe. Moreover, in highly centralized parties there are fewer opportunities for sub-elites (such as MEPs) to force Europe on their party’s agenda. To operationalize this condition, we use the CHES data scores on ‘members vs leadership’ (Bakker et al. Reference Bakker, Hooghe and Jolly2020). Importantly, as with parties’ EU opinions, we consider that only far-reaching centralization is likely to push parties in a certain organizational direction. Put differently, we are not focusing on differences of nuance between slightly more or less centralized parties but consider how outspoken centralization feeds into the causal path of parties’ multilevel organization. Therefore, parties with a high score (6.5 or more) in the CHES dataset are given value ‘1’, while all others are given value ‘0’.
Putting these values for the four party-level conditions in a truth table generates the configurations presented in Table 4. While a lot of parties seem to have quite distinct configurations, focusing exclusively on party-level factors generates contradictions on rows 3 and 5. Concretely, CD&V, MR and OVLD on row 3 all have the same values on the party conditions, yet a different outcome in terms of their multilevel organization (integrated for CD&V, federated for MR and OVLD). The same problem manifests itself for DKF, Venstre and sp.a on row 5. There are different ways of addressing contradictory configurations, and we have chosen to – in line with the literature – add a condition that focuses specifically on the individual level: seniority of MEPs.
Truth Table (Party-Level Conditions)
Notes: MAIN = mainstream party; CENT= centralized party; GOV = governing party; OPN = outspoken opinion on the EU; FED = federated party; CON = consolidated party; INT= integrated party; SEP = separated party.
We consider the seniority of MEPs to be an important additional condition because of the way it may affect the direction and intensity of cross-level linkage. Indeed, it is important to keep in mind that such linkages go in both directions, from the national to the European and vice versa. Junior MEPs might not only want more guidance from the national leadership (European to national linkage) but may also be considered by the leadership to need such guidance, or even control (national to European linkage). We consider the possibility that senior MEPs may neither need nor want such guidance and may act – both individually and as delegation leader – in a much more independent or proactive way. Moreover, senior MEPs often also take the lead in their party’s relations with their European party federation. For instance, one could argue that OVLD would not want nor be able to keep a figure like Guy Verhofstadt on a tight leash, while instead he himself might proactively steer the party’s EU position.
To operationalize this condition, we looked at each party’s MEPs at the time of the interviews and these MEPs’ prior careers. We argue that it is not the length of the career as such that will matter but rather the leverage MEPs can have to act independently and be influential in how their party interacts with Europe. Parties with MEPs who have had typically influential, senior, positions – like (prime) minister, parliamentary group chair or party president – were given value ‘1’, while those without such prior career were given value ‘0’. One specific case was Bas Eickhout, MEP for the Dutch green party GL. Though he did not have a prior ‘senior’ position at the national level, he enjoyed broad support to become the European Green Party’s Spitzenkanidat (together with German green Ska Keller) – a position he enjoyed again in the 2024 elections (this time together with German green Terry Reintke). Therefore, we consider him to fall within the category of ‘senior MEP’.
The inclusion of this fifth, individual condition produces a new truth table without any contradictory configurations, as shown in Table 5. The very fact that seniority solves the contradictions, while not creating any new ones, is an indication of its possible explanatory value. This will, however, have to be further explored through QCA’s minimization process, which we will present and discuss in the next section.
Truth Table (Party-Level and Individual Conditions)
Notes: MAIN = mainstream party; CENT= centralized party; GOV = governing party; OPN = outspoken opinion on the EU; SEN = senior MEP; FED = federated party; CON = consolidated party; INT= integrated party; SEP = separated party.
Analysis of sufficiency
It is important to recall that QCA develops a notion of causality that is based on multiple conjunctural causation and equifinality, meaning that multiple (combinations of) conditions can be sufficient for the same outcome (Rihoux and De Meur Reference Rihoux, De Meur, In Rihoux and Ragin2009; Schneider and Wagemann Reference Schneider and Wagemann2012). A sufficient condition, or combination of conditions, is one whose presence always leads to a particular outcome. To obtain sufficiency, QCA uses Boolean algebra to minimize the truth table and remove logically redundant conditions: when two formulas leading to the same outcome differ only on one condition, that condition is logically redundant and can thus be excluded (Schneider and Wagemann Reference Schneider and Wagemann2012).
Table 6 presents the result of this minimization, reporting the ‘conservative solution’. Conservative solutions only include empirically observed configurations and excludes logical remainders (i.e. configurations for which no empirical case was observed). This has the advantage of staying as close as possible to the empirical evidence, but usually also means longer, more complex formulas that require more qualitative contextualization to interpret. Despite this drawback, the conservative solution was considered most appropriate, as we have a limited number of cases available, of which we have deep knowledge. The consistency scores indicate the overlap between the set of cases represented by this solution and the set of cases with the outcome it hopes to explain. The raw coverage scores indicate how much of the cases the proposed solution explains, while the unique coverage score indicates the number of cases which are exclusively covered by the proposed solution (Schneider and Wagemann Reference Schneider and Wagemann2012: 129–139).
Analysis of Sufficiency
Notes: Capital letters in the solution mean the condition is present; lower-case letters mean the condition is not present.
Regarding parties following an integrated type of multilevel organization, one should acknowledge that the group consists mainly of green parties, in which the Flemish Christian-democrats seem the odd one out. If we first focus on the green parties (SF, GL, Groen, Ecolo), it becomes clear that, though they vary regarding government participation and EU opinion, a common thread in the different formulas is that they are not mainstream or centralized parties. In terms of causal paths, it suggests that the absence of a rigid party structure allows (non-senior) MEPs and other second-rank elites to make cross-level connections regardless of direct steering by a nationally focused leadership. Such a more bottom-up approach to party organization is typical for green parties (van Haute Reference van Haute2016), and in that sense their particular ‘genetics’ thus seem to show also in their multilevel organization. Moreover, though it does not show explicitly in the solution due to SF’s ‘0’ value on EU opinion, green respondents also highlighted in the interviews how cross-level coordination comes naturally to parties concerned with cross-border issues like global warming and environment, generating a natural Europhile position. ‘If there’s one constant and if there’s one thing that binds us together, it’s European belonging. That’s really what the Greens are all about’, as one of our green respondents reported. As such, these parties think of multilevel linkages as something obvious, driven largely by their bottom-up organizational traditions and the realization that the EGP is a valuable source for both expertise and influence – much larger than, for instance, the PES will ever be for the German SPD.
A brief look into the history of the Flemish Christian democrats indicates a similar logic of obviousness in terms of multilevel linkages. One could call it the ‘Martens effect’: for decades the party has been at the forefront of EPP development, pushing the EPP to become one of the strongest and (organizationally) most integrated Europarties (Bressanelli Reference Bressanelli, In Ahrens and Kantola2022). The fact that former Belgian prime minister Leo Tindemans was a driving force behind the establishment of the EPP in 1976, and that another former prime minister Wilfried Martens has been leader of the EPP for more than 20 years (1990–2013) are testament to this. Today, the party is ‘permeated by the idea of cooperation’ and considers it ‘unthinkable’ to not engage at the European level (different respondents). This is a good example of the interaction between the presence of influential individuals and the historical paths they set. That said, CD&V is quite the anomaly among mainstream parties, making its peculiar European history difficult to capture in measurable conditions.
Most other mainstream parties fall in the category of parties with a federated multilevel organization, making belonging to a mainstream party family the main thread across the different formulas. In other words, most (Belgian and Dutch) mainstream parties engage with Europe in a way that disconnects the transnational activities of the national party and supranational activities of its EP delegation. In line with our earlier argumentation, we consider this to be mainly due to these parties’ genetics and historical evolution. The development of the mainstream parties of the traditional party families – such as the Dutch PvdA or Belgian OVLD – is intertwined with both the rebuilding of the democratic nation state and the European integration project in post-World War II Western Europe (Conway Reference Conway2020; van Zon Reference van Zon2024). As a result, they are embedded in political institutions at both levels, though the development of the EP and its Europarties as a distinct political level (Pittoors Reference Pittoors2024) resulted in a two-pronged entanglement: they engage on both levels, but this engagement has developed independently, resulting in their current federated organization. As a VVD respondent aptly stated, Brussels and the Hague ‘are different bubbles, each working according to its own dynamic’.
Diverging from this path are the Danish mainstream parties, who form the bulk of the group of parties with a consolidated type of multilevel organization, together with the Flemish nationalists and the Belgian francophone socialists. Though the Danish parties have a different solution to that of the Belgian parties, a common thread is that they are all highly centralized parties with no outspoken opinion about EU affairs.Footnote 1 This indicates that these parties are mainly focused on themselves and their (dominant) position in national politics, rather than with European affairs. With their focus on internal cohesion across levels, an image emerges of partisan organizations that run a tight ship, regardless of which level one is active on. A respondent from Venstre captured this in stating that ‘it is very, very important not to speak with two tongues’.
Again, history can be of use to contextualize this more. For DKF and N-VA, recent histories of dramatic internal strife have left the parties traumatized, seeking recourse to strong central leadership (Wauters Reference Wauters2010). For PS, SD and Venstre, decades of struggles over who is to be top dog led them to behave like battle-hardened war machines that have ways to settle internal dissent. One striking observation is that government participation does not show as an important condition for the Danish parties. Although SD respondents emphasized the importance of leading a single-party government, and the other Danish parties lamented being in opposition, the analysis shows that incumbency status is not a source of differentiation between them.
Finally, as there are only two parties with a separated type of multilevel organization in our analysis, we must be careful not to over-interpret the solution. Still, the analysis suggests that being a challenger party – or, especially in the case of SGP, a niche party – in opposition generates a directional push towards very few organizational linkages with the European level. Not having historical connections to European institutions and not being involved in EU policymaking through government effectively means these parties have few opportunities to have a meaningful impact on European affairs. The absence of a senior MEP and presence of high centralization additionally means sub-elites have little room or authority to engage on their own initiative. If anything, this points to rational or opportunistic cost–benefit decisions to (not) invest in European connections – also implying this could change if opportunities present themselves. Respondents from DF have signalled as much, saying that, although at the time they were not a member of a Europarty, ‘we will need to consider it more in the future’ and that ‘maybe at some point the [Euro]party could be interesting for us, because other parties are there’.
That said, a striking element is the absence of EU opinion from the formula. While SGP’s ‘0’ value on this condition is the logical explanation, one cannot but consider that SGP and DF are the two most outspokenly Eurosceptic parties in the selection. DF has been openly calling for a Danish exit from the EU (see: Ravik Jupskås Reference Ravik Jupskås2019), while an SGP respondent made clear their party’s view of the EU as ‘a European community of strong nation states’. Although for SGP in particular, this might not be a major issue, it is not far-fetched to consider that such ideological inclinations contribute to a causal path towards a separated organization – why invest in Europe if you are all about the nation state? Moreover, though other parties in the analysis are rather small in size, Eurosceptic ideas may interact with more practical considerations in terms of limited resources spent on Europe. An SGP respondent very clearly spelled out the resource challenge the party is facing: ‘Our parliamentary group is most of the time trying to keep track of things happening in the Netherlands and responding to news in national media – they don’t have the time or the means to really follow up on what is going on in the EP’.
In sum, several causal pathways can be observed. Both party and individual factors fundamentally alter parties’ incentives to invest in cross-level linkages, and the final shape they take. Though the impact of senior individuals is to a certain extent idiosyncratic, the interviews have made clear that in some cases parties – such as OVLD with Guy Verhofstadt – have effectively outsourced their European activities to these senior MEPs, who are trusted by the national leadership to uphold the standing of the party. Strikingly, we see that it is mostly the Belgian parties that operate through more senior MEPs. This may reflect a different approach to multilevel politics in unitary systems (Denmark and the Netherlands) and long-term federal systems (Belgium), where European politics may be considered a more natural extension of a domestic political career. Yet, somewhat counterintuitively, we do not see this with the integrated Belgian parties, indicating how institutionalized structures and reliance on seniority act as communicating vessels.
Importantly, however, no single condition can be said to be sufficient in itself, but it is their combination that generates different causal pathways. On the one hand, mainstream parties can mostly be found in the groups adopting a federated or consolidated multilevel organization, with the combination of a non-outspoken EU opinion and high centralization generating a directional push towards more consolidation. This reflects traditional parties’ embeddedness in domestic political systems, and their ambiguity about the EU: they engage intensely with European affairs but prefer either to ensure it does not directly connect to their domestic activities or to keep it on a tight leash. In short, they want to stay in control, be it by minimizing EU contagion or through direct oversight. On the other hand, challenger parties move towards separation or integration. Particularly the greens show a rather uniform approach, which can be traced back to their bottom-up traditions that allow second-rank elites such as MEPs or European/international secretaries to engage across levels. Though not explicitly shown in the QCA solutions, the Eurosceptic attitude of the other non-mainstream parties is potentially a key difference that leads them to a completely opposite multilevel organization. If more hard Eurosceptic parties were to be included in future analyses, the importance of Euroscepticism for their multilevel organization may become more pronounced in the analysis.
Conclusion
Which paths lead political parties to organize very differently from each other in the European multilevel context? This research investigates how and why 19 Belgian, Dutch and Danish political parties organize their interactions between the European and the national level. We study the place given to MEPs in the national party organizations, the importance of the Europarty and of EU-related topics in the national parties’ daily organization. Based on rich qualitative data, we conducted a QCA that helps us explain why these parties differ in how they (do not) connect the national and the European party organizational levels.
A key take-away is that there is no single way to understand why a national party handles cross-level linkages the way it does. It is rather a combination of factors leading national parties to a particular kind of organization in a multilevel context. In this study, we deliberately chose not to integrate country-level factors because we contend that parties do differ from each other within each polity, so we need to go beyond factors valid for all parties in one polity to understand the specificities of how parties organize. Our results show that explanatory factors situate both at the party and the individual levels. A major factor relates to the genetics of parties: parties from mainstream party families do differ from niche parties in how they organize in the European context. The latter adopt ‘extreme’ strategies on how to make room for the European level in their national organizations: either they deeply integrate both levels (a typical strategy of green parties) or they almost neglect the European level (a typical strategy of Eurosceptic parties). On the contrary, the former situate in the intermediary categories with two distinct approaches: either parties from mainstream party families choose to focus on their linkages with sister parties abroad, and their umbrella Europarty, holding only ad hoc linkages with their representatives in EU institutions (a typical strategy of centre parties like MR or PvdA), or they instead rather neglect transnational links to focus on their MEPs but through close control of their activities and to serve the interests of the national party level (a typical strategy of parties like PS or SD).
Moreover, parties are not just faceless institutional structures, but are populated by individuals with specific preferences and experiences. As our analysis shows, at times these individuals can have a major impact on the way parties behave in a multilevel context, particularly where institutionalized structures are weak or even absent. Yet, while relying on senior individuals may be a cost-efficient way for parties to deal with ‘Europe’, it holds several risks, such as agency drift or the loss of stability and influence when that person leaves their post. Particularly in countries with a limited number of MEPs, a single MEP can make the difference. Moreover, what counts as a ‘senior’ MEP might differ depending on who is asked: someone with a long period of service in domestic politics might be considered ‘senior’ by the national party leadership, but hold zero sway at the European level – and vice versa.
This research has established the need for opening the black box of political party organizations to understand why they are organized the way they are. Excluding party- and even individual-level factors leads to missing an important part of the story: current but also past dynamics within national political parties can help us appreciate how they apprehend their interactions with the European level. A second key lesson is that one cannot merge all aspects of the European stage around one single factor: national parties do diverge in how they interact with both EU institutions and other actors at the European level such as the Europarty or their sister parties across the continent. We encourage further works to extend this research path by investigating other national parties in other European countries and taking into account the horizontal dimension of parties’ organizational strategies in the EU. It is, for instance, likely that multilevel dynamics have different roots in parties from large countries or from countries where Euroscepticism is more present than in the three countries under study in this research. The relevance of belonging or not to a mainstream party family could be investigated in the case of parties from Central and Eastern European countries where these families exist just as in the three cases researched in this study, but where the individual development of the mainstream parties was not concomitant to their party family development. Moreover, scholars could look into those party characteristics that explain why some are more interested in coordinating directly with sister parties abroad, such as the radical right (McDonnell and Werner Reference McDonnell and Werner2019), rather than in vertically interacting with EU-level structures. Such a research agenda contributes in important ways to a better understanding of party politics in the EU and hence of the EU itself as a democratic polity.
Supplementary material
The supplementary material for this article can be found at https://doi.org/10.1017/gov.2025.10009.
Acknowledgements
The authors wish to thank the interview respondents for their valuable time spent talking to us, and the crucial information they provided us with. Thanks also go to the members of the GASPAR Research Group of Ghent University, in particular Bram Wauters and Benjamin De Vet, and several participants of the 2024 SGEU Biannual Conference in Lisbon, especially Wouter Wolfs, for their highly valuable feedback on a previous version of this paper. Special thanks also to Ghent University’s Tim Haesebrouck for his precious advice on QCA. The authors also want to thank the reviewers for their critical and helpful comments, and the editorial team of Government and Opposition for their smooth management of the publication process.
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