This chapter set out to test empirically whether parliamentary parties' inclinations towards intergovernmental or federal constitutional preferences, as well as the nature of existing parliamentary institutions in the member states, explain their choices for or against parliamentary oversight institutions in EU affairs. As discussed in the previous chapter, the analysis relied on a measure of partisan support for European integration as an approximation of intergovernmental and federal tendencies in partisan preferences. However, all the results also hold true if we replace this operationalization and instead focus on whether parties are in favour or opposed to empowering the EP—a measure that should be more closely related still to their views of the right constitutional design of the EU polity.
Re-visiting the main findings, the first part of the chapter investigated the relationship between the explanatory variables and level differences in the strength of oversight institutions across the member states at the end of each of their reform opportunities since the mid-1980s. The results clearly support an explanation based on constitutional preferences and domestic institutions (e.g. Winzen etal. 2015; Dimitrakopoulos 2001; Raunio 2005; Karlas 2012), while an alternative view that emphasises incentives related to minority government and coalition conflict has to be rejected (e.g. Bergman 1997: 381; Martin 2000: 154; Saalfeld 2005). In particular, the view that minority government determines parliamentary adaptation to integration has emerged on the basis of a selective emphasis in the literature on the Danish experience, which indeed appears to fit this argument, while ignoring other examples of countries that combine robust majority governments and noteworthy EU-related oversight institutions such as Austria, Finland, and Germany.
The second part of the chapter adopted a different empirical perspective, focusing on the conditions under which parliaments are likely or unlikely to make use of the reform opportunities that arise as a result of the development of European integration. This approach focuses on changes at particular points in time and, thus, abstracts, to some extent, from the temporal dependencies in the development of oversight institutions that naturally arise from the fact that each institutional reform builds on previous achievements. This analysis also underlined the important impact of parliamentary EU support. Where partisan configurations in national parliaments strongly favour European integration, and can thus be said to tend towards federal constitutional preferences, reforms that strengthen EU-related oversight institutions at 'home' are highly unlikely, whereas they become almost certain otherwise. This analysis also drew attention to the fact that, in selected circumstances, conflicts between cabinet parties over the desirability of European integration can motivate the creation and strengthening of legislative institutions. The underlying mechanism offered in the previous chapter is that each governing partner wants to bring in their parliamentarians in an effort to monitor whether ministers from the other side pursue excessively EU-friendly (or Eurosceptic) policies at the European level. Empirically, however, few real- world cabinets are sufficiently divided so as to really encourage institutional reforms in EU affairs. The findings regarding parliamentary institutions existing in the member states are peculiar. Whether parliaments have strong committee systems does not affect the likelihood that parties make use of reform opportunities in EU affairs. However, there is a clear relationship between committee competences at home and the magnitude of reforms. Where committees are strong, and parties decide that EU-related parliamentary rights and capacities require reinforcement, they will implement far- reaching changes. Where committees are weak, such changes tend to be far more incremental.
Interpreting the findings in light of the theoretical argument put forward in Chapter 3, two points stand out. First, the evidence speaks out in favour of the view that partisan constitutional preferences, as approximately captured in their support for integration, explain patterns of and reform choices in national parliaments' institutional adaptation to EU policy-making (Jachtenfuchs etal. 1998; Rittberger 2005; Winzen etal. 2015). Where the party composition of the parliaments of the member states wants to see an intergovernmental architecture for the EU polity, they regard parliamentary competences at the national level as necessary, and accordingly reinforce EU-related oversight institutions. Where, on the other hand, parties tend towards federal constitutional visions for Europe, they agree with the empowerment of the EP at the European level, and see little need for significant reinforcements of parliamentary authority at 'home'. Consequently, their domestic reform efforts are absent or minimal at best.
Second, in addition to constitutional preferences, domestic institutions also matter as they reflect past constitutional battles and domestic views of the right way of organizing the political system that have since become consensual among most relevant parties and policy-makers (Marcussen et al. 1999; Dimitrakopoulos 2001; Schmidt 2006). As Marcussen and colleagues (1999: 617) point out, reform options in EU affairs have to resonate with the principles and preferences enshrined in pre-existing institutions. Dimitrakopoulos (2001) equally argues that existing institutional practices in the member states constrain the range of parliamentary reactions to integration that relevant parties and parliamentarians consider legitimate. The results here support these arguments. On the one hand, they suggest that existing institutions do not in and of themselves encourage parliamentary reforms. The likelihood that parties consider it necessary to make use of reform opportunities does not depend on existing rights and capacities of parliamentary committees at home. On the other hand, however, existing institutions constrain the magnitude of reforms, which suggests, in line with what Dimitrakopoulos maintains, that only small and incremental institutional adaptation happens where parliaments have generally had few policy-making rights and capacities. Far-reaching adaptation to EU affairs is only possible where this is compatible with the principles and preferences underlying preexisting domestic institutions.